ember - 5:17 pm on May 9, 2013 (gmt 0)
Dfp isn't a trick, and I have emails from both adsense people and dfp people saying it is all right to do it if no hardcoding, etc. is involved. I have also attended Adsense in the City events where we were told 4 ad units run through dfp, if done correctly, is okay. Having said that, I do not run 4 ad units per page.