I'm sorry you had a negative experience with your tease. You took a risk with a
truly interactive tease and that kind of thing should be encouraged. I think there are a lot of cool elements to the idea.
However anecdotally it seems that most password locked webteases get bad ratings, no matter what the content. People don't like being 'locked out'. There was a large number of teases by odawg that required passwords, and people voted those down to, because they were annoyed they were locked out I guess. I don't think it's right of them to do that. It's mean and unnecessary, but people can vote anonymously and anonymity makes people mean for some reason. Some people that stumble on a tease with a password lock are going to downvote it. I don't know why really even, but I guess it makes them feel good in some way. It's a way to say "screw you for excluding me" I guess. Not sure, but that's the way it is.
As for the tease idea itself, most people feel it's very risky to send personal information to an anonymous person. However, I'm not sure how to implement a blackmail fetish without personal information!

I can see the excitement in the idea though, but it definitely has to be someone you trust is not a scammer and maybe something with slightly lower stakes. Like what if a person takes embarrassing pictures and if they fail the tasks, the photos are posted to a thread here instead, or maybe even only to other participants? That would also allow you to build a tease that that doesn't require couples and so includes more possible players. I feel that single people are more likely to take part of a real-world blackmail fetish tease as well, because the stakes are lower.
Lot's of people might have a blackmail fantasy, but bringing it fully into reality is a big step. Same with financial fetish domination, which is related I think. I imagine can be very exciting fantasy for some to associate sexual pleasure with the anxiety of giving away money one can't afford to give away. However, even though clips on this fantasy are very popular, I doubt there are very many people that actually move from fantasy to reality. The leap is too large and if anything shows that there are some fantasies that should forever stay only as fantasies for most people.