I just picked up this lovely fitting bcd, and I am curious if all these instances of weight drop are from the bucket coming unlatched or the webbing pulling out? Mine came improperly webbed with only 2 of the three loops through the slots. As they are new, it looks virtually impossible to slip out. But with wear and water, I can see how it may. Simple solution is the ziptie method mentioned. And, as many have stated, don't rely on the integrated weights for 100% of your weighting system. Cold water divers will have to use a weight belt with it anyways, since the integrated (minus trim slots) only hold 26lbs. I take 45lbs minimum in pacific saltwater and double 7mm neoprene.
Anyways, are there issues of the buckles unlatching or just the webbing coming undone?