That's what I thought when they were trying to create mini black holes with the super collider. They said the chance that a black hole would grow and swallow the earth was very, very, very small. However, the chance was not zero. And there was nothing practical to be gained, only knowledge of what things might have been like in a fraction of time after the big bang.
I'm a firm believer of looking at life on a risk vs. reward basis, and the reward is nothing but a few lines in a future textbook.
BTW, I just replaced my tag line with your line. :-)
;)