Ok, so this is kind of pathetic, but my main account was banned over a week ago but I am attached to my subreddits enough that I kept browsing. You can totally navigate your subreddits, you just can't comment. They even let you up/down vote though I doubt it actually gets counted.
Anyway - they can totally still serve you ads from a banned account if you are a fool like me.
Oh damn. That makes a lot of sense.