"We do not typically permit advertisers to manage multiple accounts featuring the same business or keywords."
The simple thing to do is ask google. Unless you are trying to game the system (as many do) they wont ban you, I think they'll just link your accounts and prevent you being able to double serve accidentally.
I would love to have a second account just to run the CPM campaign run to its full potential. I am not trying to double serve just get the most out of it.
If they know you have 2 accounts they will link them and they will act like 1 account, unable to double serve.