CPI Advertising campaings - problmes if using more than one SDK?


Let me say you want to run a CPI advertising campaign in order grow your user base and decide to use (say) Tapjoy, appBrain and Facebook.

All they require you to integrate their SDK into your application.

My doubt is: how do we know for sure that a user acquired by Tapjoy won’t be accounted and billed as coming from appBrain and Facebook too (and vice-versa)? In this case you would pay it 3 times for the same user (one time for Tapjoy (that provided the new user), to appBrain and Facebook).

Or is it not possible to know and we should install the SDK from just one enterprise and stick with it to run our advertisements ?