Author's note: This is a response to a question, which I have included, from a homeschooler. The answer; however, can apply to any inappropriate behavior, at home, a playground, a restaurant, etc.
"Though I am not up on much of the theory yet, I have created a few works of pouring, spooning, sorting, etc and put them out for the kids. I did a presentation for each work, demonstrating how the work should be done. The first day went pretty good. They would get the work from the shelf and do fine with it. I did have to gently remind sometimes to put things away before getting something new, but they were pretty much on task.
Today was a different story. Today they wanted to test the boundaries of this new system. They tried to use the work items inappropriately. Pouring instead of spooning, spooning into the tray instead of the dish, etc. They would also run to get a work, get it all set up, do about two or three motions, and then declare themselves finished and want to put it up.
What is an appropriate response to these issues? Do I insist that they finish a work before putting it away? What is the Montessori approach to doing that to avoid a battle of wills (and in our house, a time out). What is the response when they don't use the materials as designed and presented?
In addition, my daughter wanted to take the sorting beads and lay them out in a pattern instead of sorting them? What would be the response to that? To me, she is doing something wonderful, but is not doing the work as presented."
There are several things that are important to be remembered here. You can of course choose to be more open ended with the works, but then you are not practicing Montessori. If you are not practicing it as fully as you can, you cannot expect the same outcomes (self-direction, self-control, normalization, concentration, independence, etc) that goes along with a Montessori education. I'm not saying that this is a good or bad thing for your family, every family must do what they feel is correct. This is just a a statement so you are aware of what to expect or not expect.
There are a few things that could be at work in your setting. The first day they may have worked properly because it was new and interesting. The second day, not as much. This could indicate that these activities are below/above their working levels. The works could also just not be interesting to them. The first month or so the key is to observe, observe, and then observe some more. This will help you to see their working levels, so you can keep appropriate materials out. They could also be testing out boundaries as you said, and if that if the case, you must make sure to keep your boundaries firm. Montessori is "freedom of choice with limits." They can choose any of the works available to them at any time, but those works must be done properly.
So, to answer how to handle this. If they have had a demonstration and are working improperly on purpose, a redirection is what is in order. They can work properly, or they can put it away and get a new work. I usually give three chances to a student. First, I gently put my hand on their should and quietly say "You can work on this properly, or you can put this work away and choose new work." If they are still working improperly: "You can put this work away, or I will put it away for you." And finally if they do not put the work away: "I am going to put this work away now, you can return to it tomorrow if you are ready to work on it properly."
I know in one reply someone said a teacher would not allow a student to work on something without a demonstration first, and they thought that was too controlling. I would agree with that. Sometimes a student can pick up work without a demonstration and do the work correctly. Sometimes they cannot. If you are observing you can see that the work is not being done correctly and then you can do a demonstration of the work. A correction of work that has never been demonstrated; however, should not be done at the time of notice, but rather wait until the child is fresh. It is a blow to their confidence to think that someone is always waiting to correct them and this impedes their confidence. Also, do not mention that they were doing it incorrectly, a redemonstration (maybe several) will correct that. This is also the protocol if they are not doing the work correctly because it is too difficult (instead, demonstrate a work that is more at their level but will help them to work on the activity they tried at some point in the future) or if it is just an honest mistake in the work. She also said another teacher allowed them to do what they wanted to with the materials. This is too liberal. Certainly students can make extensions with the materials if they are expanding their skills, but just "playing" with the materials as if they are a toy is not what they are in school for and is a waste of time. If a student is doing extension work, they should have mastered the original material and then be getting be getting something useful out of the extension.
If a misuse is occurring, it may be the students way of telling you they would like a different work. For example, if the student is pouring dish to dish, create a work that allows they to do this. If spooning to a plate is what is desired, make an activity to do this. In the case of the beads, you may want to add a work that allows her to make designs using beads (not your sorting beads, but craft beads or the like), as well as a study of artists that have done just that. You may also want to remove the works that they are not using properly/are uninterested in. Redirect the misuse, but the next day the new works should be awaiting them.
I was disturbed by something in your post. You said that you use time-outs. I just want to emphasize that time-outs are a form of punishment and are NOT Montessori at all. A child learns nothing from a time-out (or any form of punishment or reward) except that they will be punished for not complying to an adult's wish. Instead, a Montessorian would use a combination of redirection and then understanding the root cause of the behavior (through constant observation) and then adjusting the environment of the child appropriately. Natural consequences are key here. If something is used improperly, they may not use it (a natural consequence). If something is broken, they must fix it or it is lost (not to be replaced). Again, a natural consequence. A time-out is an artificial consequence and no learning comes from it, other than to know that they do not want to get caught for fear of punishment. It does not actually curb behaviors, only curbs behaviors when the punishment could occur.
