I personally dont use mouseovers unless it's on a whole page. (which if I was doing tgp's or free sites would be declined since it's in a script tag)
If I really want to hide my code and submit, I set up a php header:location jump page and link to that. Seems to be generally acceptable provided of course that it links to the advertised site. Plus I can track outgoing clicks that way.
Doing a simple mouseover and mouseout code on each link makes the code:real content ratio pretty poor, and I think se's and other bots like to see more content than code
I really think that in general, mouseover codes have become ingrained so much that a lot of people simply do them because they've always done them so they'll always do them, lol. Firefox has evidently decided that the window status bar has become more irrelevant than relevant, so they've disabled allowing it to be changed by default.