7Soul : If you cut a global variable from an event sheet, it will indeed delete the events where the variable was used.
But you paste it in the destination event sheet in the same project, all the events come right back.
@aridale : There is a "code checker" going in the background as you are making your events. It is to ensure that the program (your game) will execute safely no matter what you coded (from a low-level perspective, the one that C2 obfuscate from you to let you focus on your game's logic instead on technical aspects of rendering, etc...).
Removing this "feature" is not a good idea. It would probably end in more bug reports and confusion for new users.
Just be logical and plan a bit ahead the order of your events and all should go well.