I'm no license expert
Neither am I :) but then someone who propagates spam for a buck .. probably isnt going to be either, or even want to be.
Wow. I didn't know the situation was that bad.
Its not, BUT, there are those cases where bad things happen.
For example, I helped a person on these forums rather recently, that was trying to figure out where the spam links inside her posts were coming from -- it turns out the the theme author had actually put the links inside the loop, so every post she made was going to have links attached to it.
Lastly, it would be nice to be able to rely on the community - but that community is largely anonymous, and vastly under-educated. And while that might be arguable - I dont trust my own sites security to someone else :)
if your interested in the hubbub that sponsored themes has caused -
and then from those that spoke out on their own blogs: