I used to work at a crappy advertising agency. They called themselves a new media business, but they just sold pop-up ads, full-page flash ads and small promotional flash sites for various customers (Sky News, NatWest, all sorts of on-line magazines, etc.). They sucked. Never have I worked with a bunch of more unscrupulous people. They wrote massive libraries of javascript to bypass some of the in-built security restrictions in the major browsers, and seemed pleased that they'd circumvented something the designers put in on purpose to stop idiots like this doing it.
Anyway, during the interview they never mentioned their business was flash adverts. It was only when I started did they tell me. I hated the job from the get-go. I just sat at my desk, wasting time, coding all sorts of PHP. It was good, though. Getting through their firewall taught me about SSH tunneling, and it opened my eyes to the hideous world of marketing.
They really sucked. I ended up walking out of there. I figure it's not worth doing something unethical. Even if you can bring yourself to do it, it'll catch up with you later on. You can't hide from yourself.
If I worked at that dating site, I'd let them know, in no uncertain terms, what I thought of them and their organisation.