I never had things taken off our door, BUT, I make it rather difficult to do. I have always put up fishing net over the door. It works well and looks cute. When I have a moment I will post a pic if I can find it.
There is a trick to hanging it so it can't easily be removed too, it takes a little work, but PM me if you want instructions. It helps I think because it takes too long to get sticky fingers under the net and nab a magnet, kind of like that ADT alarm sticker people have in front of their home....go to the easier door to get magnets that may not have a deterrent.
(I know some people that just have the sticker without an actual alarm
)
As far as FE we zip tie it as well. I use toe nail cutter to get it off. As far as the gifts, well I don't know for sure. The only FE we participated in had 2 days of delivering, not because of control the FE, but as a security measure to prevent sticky fingers. I don't recall anyone stating items went missing.
The cruises after that were shorter ones and I opted not to do FE but always had that fish net covered door, so if you saw one it was probably us.
We started doing that back in 2012 after hearing about magnet theft I think on here....