Ofcourse it's bad to bot 24/7. I pretty much do it anyway. What I'm wondering though is, does it make any difference if you switch chars? Or is it per account? I'd assume it's just based on the account but switching characters and doing say 6 hours on each may not show as obviously on their end. Does anyone have any experience trying both?
Well if you switch characters it could imply that a friend of yours or a family member is getting on to another character. Even better for another account as you have more of an alibi of a friend or family member playing.
If you don't have any friends added i would say 24/7 leveling is safe 1 account or one toon, it depends on the server population too.
It's probably a bit better than a single char 24/7 botting, due to being a lower profile, and even if another player is on to you, there's no way to tell if 2 toons are on a single account. As to friends or family members playing, that in blizzard's eyes is just as against the rules as botting, and just as bannable. Unless it's a minor child and an adult sharing an account, but I doubt they would believe you if you told them.