I've used Blaser mounts a ton over the last five+ years on many barrels (mainly NF scopes). I don't abuse my gear, but it's carried and used a bunch along with mates that use them for culling. I've never had the Blaser mount lose zero even after multiple mounting/unmounting. Neither has anyone else I know using them.
If they had any weakness, maybe I could say the rings as they are not steel from what I can tell. But side to side I can't see a situation where they are moving without physical damage to the mount. If there is a way for me to test this theory I will try if someone can come up with a non-destructive method.