I think you're referring to dump-able weight pockets attached to the BC with Velcro, not the XS scuba type that threads on the waist-belt or cam band, and has a Velcro closure. The XS scuba pockets only hold one weight each, the Velcro is not holding the weight in place (it's not on the bottom unless you're upside down) and are very reliable.
I think that we are talking about the same pockets. If we are, those pockets hold up to 5lbs each. With everything that I've seen, a lot of divers are just getting gear and don't necessarily think about mounting and asking questions. I've seen divers entering the water with those pockets facing down instead of up which is a potential problem. Even when facing up I've seen divers doing head first, feet up in the air (can't make this up) descents which can lead to a weight falling out and lastly I've seen divers get in all different positions underwater which can lead to the same scenario. All in all divers will continue to use them, my preference is to use a style that doesn't rely solely on Velcro.
I think that we are talking about the same pockets. If we are, those pockets hold up to 5lbs each. With everything that I've seen, a lot of divers are just getting gear and don't necessarily think about mounting and asking questions. I've seen divers entering the water with those pockets facing down instead of up which is a potential problem. Even when facing up I've seen divers doing head first, feet up in the air (can't make this up) descents which can lead to a weight falling out and lastly I've seen divers get in all different positions underwater which can lead to the same scenario. All in all divers will continue to use them, my preference is to use a style that doesn't rely solely on Velcro.