I wrap text inside of the link tag all the time.
http://www.kinkycleo.com/porn/boobs/...tgp/index.html
I build a lot for TGPs and their scripts count <a> tags so to make it past the script you need to really keep down the amount of <a> tags.
I usually put my banner at the top of the warning page so that is the first thing that the surfer sees. I also usually put a scraper link under my enter link for the ones that want to scroll past everything.