While the requested app isn't something you'd actually make, it's a useful request in that it's a real problem, and people voting it up indicates they want a solution to that problem.
The essential trait in a startup founder is the ability to find workable solutions to problems people want solved. This is the public doing their part, now founders have to do theirs.
However, there's potential for a lot of "abuse". The top suggestion now is:
I wish there was an app where you could report a car whose alarm has been going on for hours, and car thieves will read it and steal the car
I hope you don't try to ban that sort of thing, though.