Would it be possible to setup multiple PPC Campaigns across multiple sub folders?

[Webrevolve]

...or would it count as double-serving?

Our client wants to give control to local franchisees within his site - hence having different PPC Campaigns that can be managed separately on individual sub folders within a multi-site.

I'm assuming this would be fine but require some reassurances!

[BrightHealth]

That's fine, you can do that if you want. Read more, here. I don't like doing this unless it is absolutely necessary, mainly for two reasons. The first, display URL's character limitations gets to be frustrating.. unless you have a great short domain. The second, billing & reports can quickly become a nightmare. Set up as their own accounts, you will be fine though and the quality scores should be generated from the respective sub domain only.

[Webrevolve]

I say sub-domains. I mean sub folders. No idea why I got mixed up.

Does the same apply?

[DavidKonigsberg]

Unless your using two different accounts google will only show 1 ad per keyword. Double serving only becomes a issue when you are serving 2 ads under the same keyword and location etc. Are the local franchises in the same area? If not no issue-  Google is trying to prevent you from filling up the page with the same companies results.