Good topic. I currently use 10lbs on a weight belt with my LP 95's, but I keep it under the crotch strap just in case it accidently unbuckles. I intend to get a v-weight one of these days and do away with the belt. Of course, I'm a dry suit diver so if my BC fails, the suit will certainly get me up. I'm also pretty well balanced and am able to swim up if need be. In addition to all of that I carry a Halcyon 80lb lift bag and reel. Finally, if there's a really bad CF going on, my buddy is set up axactly the same way and he'll get me up.
I'm an overhead diver (primarily) -- be it solid like a wreck or a deco ceiling -- so having a belt accidentally come off and shooting to the surface is simply not an option. I'm not a wet suit diver, but if I were and was doing ceiling stuff, I would still keep the belt under the crotch strap to prevent an accident. Ditching it would be the last option. I'd carry a lift bag, try to swim up, or utilize my buddy before I'd ditch the belt. IMO, ditching the belt should be a very deliberate and well thought out event and not be taken lightly for any type of diving -- especially ceiling dives. I'll even go out on a really long limb and say I beleive it's one of the worst practices taught in the industry because it leads to negligence and a false sense of security. Now that should get ya'll wound up!
Take care.
Mike