Most of them don't really care. If you are really worried, you can either:
a) Make it "look" legit so if your network investigates they won't see it's completely fake
b) Blank referrers using a custom content locker (I've never done this but I'm sure many members here have)
c) Use the old download, rar/zip and password trick.
I would say use FileIce (PPD) or AdworkMedia (CPA).