In my experience, eventually the adhesive becomes gooey and the stickers will creep around under minimal force. By that time the printing will be mostly worn off the stickers, and the paint on the palm rests will have been burnt thru.

Are not the shells of most thumb drive plugs made from plated brass? Thus non magnetic.

Many lappies have one or more magnets and opposing magnetic switches in them. I'd be surprised to find a new one that didn't. MacBook Pros snap closed because of some pretty strong ones.