I've had content lockers accepted in the last 2 weeks for tv/movie niche, so they can't be too fussy!
Splash pages to gain referrals work ok too.
I've seen a lot of adverts with adsense on as well.
I think the page load time might have something to do with it. Content lockers sometimes take longer than 5 seconds to load up and I think they take that into account. It may be as simple as that.
I'm quite active on their forum and as far as I can see as long as you don't advertize porn or warez and don't have frame breakers they're pretty accomodating.
PS, best not to try Amazon links, adfly breaks Amazons terms apparently. Youtube is no good either... EPN is ok though...