DMR would be okay....unless you're afraid of their being too many blank refs and causing problems with the network. You could easily write a script that would randomize between blank and spoofed refs.
However, you also have to consider what kinda of PPC campaign you're attempting. If you're doing any domain squatting, or just bumping heads with the advertiser on their keywords, you're liable to get caught. You have to wonder why the advertiser doesn't want you promoting by adWords....
