Do Not Touch Signs

I am a kindergarten teacher. One of my favorite things to do is teach my kiddos how a 3D printer works. I even help them design something simple in Tinkercad and then we print it. It is a lot of fun!
My only concern is that my little impulsive puppies will touch my printer while it is working. I am not really scared that they will burn themselves. The hot end is tucked away under my fan ducting and they would really have work to get up under there. Mostly, I do not want their dirty little fingers on my print bed. :) I made these signs to help keep them from touching the printer.
I designed them in Tinkercad. I added a little channel on the bottom of the sign to help it release from the print bed. A little squirt of 50/50 alcohol-water solution helps these flat prints release. The channel allows the liquid to get under the print a bit better.
I printed them in white and then used some sharpie to add color.
I put a couple magnets on the Do Not Touch sign so it is movable. The Hot