I have extensive work being done in one of the rooms in the house. For their own safety, I would like to keep curious 3-to-6-year-olds out of that room. The door to the room has no lock, and opens inward into the room.
I will of course explain to the children not to go there, and put appropriate incentives for compliance. However, I do not expect this to be 100% effective, and so am looking for a mechanical solution as well.
Note that the solution need not be 100% effective. For example, if a child needs to fetch a chair to stand upon to unlock the door, that is acceptable. I just want something to protect from impulsive "I am just going to take a small peek, I promise." Because this is only for a couple of weeks, I do not want to install a lock. Ideally I would like not to have to repaint the area either.