I am glad to hear the worst you got was a scare NAro.
Snagging on stuff is why I don't wear anything on a cord around my neck, why I only wear weak watch straps and why I don't wear rings.
I also have a habit of checking my gear for loops that can snag too.

On a side note;
If you snagged on the raft's grab line others likely have too. It might be worth thinking about a safer way of providing that grab rope feature.