I'd love to see how Mercedes and the others engineer those ones that flip up...it's got to be hinged on just a couple of thick bolts, right? I supposed that hinge connects to the frame somehow? Time to google...
Ok here is something interesting I found:
"The 94 fatalities attributed to 87 convertibles that rolled over in 2004 accounted for fewer than 1 percent of about 10,000 U.S. rollover deaths last year."
(good article)
http://www.autosafety.org/article.php?scid=174&did=1183