I found with the magnetic sheets that they tend to have enough weight themselves that is why they tend to move or slide. I don't necessarily think that they repaint the doors to all the staterooms that much to build up a that many layers of paint, nor do I suspect that during the Wonder's dry dock stripping every single stateroom door was a priority at that time. I would not count on them being any different paint thickness wise than before the dry dock. I do suspect that the strength of the magnetic "sheet" is dependent on the manufacturer adhering enough of the mineral that gives it it's magnetic quality to make it hold to a metal surface. I've found that many of the magnetic sheet's that are sold online often have significant complaints about their adhesion ability to things like appliances or other metal surfaces. That coupled with the cost of the magnetic sheets in the first place, and the potential if you have a issue printing a sheet and it doesn't come out like you want it to, it's just wasting one for the purpose, has steered me to printing the door decorations out on heavy card stock and laminating them. Then attaching self adhesive magnetic squares to the back my method for stateroom door decorations.
