Manufacturers' first attempts at waterproofing usually result in completely glued devices, oftentimes without a non-destructive means of entry. Looks like things are going to be different here.

The glass lens cover is probably the most likely part to break on the Session, but it's also the easiest to replace. It's good to see that GoPro had repairability in mind for the lens cover, as they sell a complete lens cover replacement kit.