Everything in that event sheet that uses it will remove it at that point correct? Seems like the warning makes sense to me, if the variable is not global, and is removed from the event sheet then any references to it will break. Or am I misunderstanding?
Unless you are talking about global variables, in which case there is no reason to move them between sheets because they are global. If you are worried about seeing them it may be easier for you just to have an event sheet dedicated to global variables.