Originally Posted by abhorrent

A lot of the "adsense ready" themes have the designers ads in them.
Usually the read me file will say "replace my pub ID with yours" or something similar.

They do it so you can see how it looks in the demo (if they have one) and leave it there because it makes it easier for people who don't know how to code. They just change the ID and they're set. Otherwise they get a million emails ("How do I get my ads in the theme like in your demo?")..

I'm sure they hope that some people will forget to remove or change the ID but I don't think there's anything too sneaky going on.