Nobody is going to flip their vehicle, no matter what kind, unless:
a) They are a bad driver and don't know how to handle their vehicle.
b) Someone else causes the wreck.
c) Some freak circumstance occurs and it is the will of God.
Many people who get in major wrecks that are their own fault end up wrecking many cars in their lifetime and would wreck just about anything on wheels. I used to own a Ford Bronco (which I couldn't have flipped if I tried) and I used to drive a Ford Explorer, but I'd know when I'm driving that Explorer that it's not going to handle like my mom's Taurus and I'm not going to be able to manuveur (spelling?) it like a car, so I handle it with a little more respect, and maybe I'll brake a little bit more in the turns or slow down a little more when it's wet. If someone doesn't think they can handle driving an SUV, then they shouldn't drive one. Same applies to other cars, motorcycles, planes, etc.
I'm sure if there was a study on the likelyhood of a bicycle crashing vs. a tricycle crashing, then the tricycle would be deemed the safer ride. And if there was a study to see if riding a tricycle was more perilous then walking, I'm sure it would show that walking would be much safer. And if there was a study to see if walking was inherently more dangerous than sitting down in a padded chair in a locked room..... I don't think the answer is to ban tricycles, bicycles, or SUV's. I think some people should be more competent when they are handling a 3000 lb vehicle. So instead of being anti-SUV, I guess I would be anti-bad-drivers.