Oh.... Forgot to share a funny story....
I worked for a kinda family shop, (3 brothers) youngest of which was to take me out and show me the ropes...
During his long diatribe about "Always follow the neutral back to the buss bar so you know you're pulling the right... Doh.... Go inside and see if I blew any thing up!" I go inside and the horrorfied customer is sitting in front of her smoking monitor. That wasn't funny, but that guy explaining it to his brother was...
Anyway, things happen... And it is common sense to shut adjacent circuits in any box off when messing with neutrals. Go as far to have customers up-plug computer or other equipment while you are doing so. Best thing to do is put an amp clamp on any neutral if it has a remote possibility of being shared. That is still not a guarantee, but does help you to say no if it does have any current.
