I assume these have the old fashioned hooks on top and bungee on the bottom type setup. Personally I think that is fine and I even prefer it. It is a simple and effective setup. Pretty much all panniers were that way at one time and I always figured that most of the newer attachments were not really that much of an improvement. If paranoid, a cable tie around one of the hooks or a strap connecting the two panniers at the top could be used as a fail safe in case the hook comes unhooked.

These panniers appear to be on the smallish side, which I consider to be a plus, but if you pack a lot it just might become an issue.