oddsod - 3:22 pm on Mar 2, 2009 (gmt 0)

Create a few pages on your site that are pretty worthless. Interlink them. Have just one minor link to one of these pages i.e. give Google and other bots a way in. Then put other people's publisher IDs on those pages. Lots of different IDs on different pages. Get reputable IDs from the big boys - NYT, Amazon, Ask, AOL. You don't lose any income, you don't lose any PR, it's within the Adsense TOS and you frustrate those data collectors ;)