This is one of the ones where I question snopes. Modern agriculture has made it so that the incidence of trichinosis within pigs has virtually vanished. If you attempt this experiment with an uninfected piece of pork, of course it's going to fail. And, the vast vast majority of pork that makes it to market are unaffected. That doesn't mean it won't work on a piece of affected meat.
For what it's worth, I frequently encounter little wormy things inside the flesh when I'm filleting fish. I'll pop one out with my knife on occasion if some kids are watching me do the fish, and show them how the worm will squirm around on the table. Doesn't phase me though - it's just a little bit more protein when I cook the fish. However, these are in wild fish; since farm raised fish are fed, it's not that difficult to monitor them for parasites or to administer different medicines to kill off the parasites. Thus, you won't see the parasites in those fish. I've never noticed any in venison or other wild meats before though; although I've run into a few huge, disgusting botfly larvae in squirrels before. While they won't harm the meat, I still discard the carcass out of disgust.