I wanted to sign up to the mpreg fest but then I thought it would be cruel to my recipient. :P And yes, I'm also guilty having left some WIPs behind. (Amazingly, I still believe that some day, I'll get back to that fandom, at least temporarily, and finish that fic, because I really liked it.) But I haven't experienced the losing-confidence in my fic's main topic - perhaps because neither was very risky to begin with.

And you're welcome to adapt any tactic. To be honest, I sometimes go through the sign up posts of fests I know I won't sign up because it's not my pairing or not my type of fest, and steal the likes and kinks that make me go oooh, but I haven't thought of them on my own. *snickers*