Gotta love the folks who have been lucky so far and thus seem to feel superior to those other folks who obviously don't know how to install the bags properly. I'm waiting for one of them to come back and report that even they have finally been bitten. Assuming they would fess up to being wrong of course.
With all the variability in Harley's bikes and accessories, why is it that some people can't seem to believe it's possible that some bags, even when properly installed, have and can come loose? Most of the many faults found on Harley's aren't in the 100% category, some fail and some don't. If you have one that doesn't suffer a particular failure that is common on other bikes, it's much more likely to be related to chance and not some superiority of the guy riding the bike.
As the fireman once said, where there is smoke there is often fire.
Jerry