I am unsure exactly what you are referencing with “tube-clamps”. If you mean hoop-clamps or hose-clamps, then those usually have “self-cantering” hexagonal heads as well as the slot: https://duckduckgo.com/?q=stainless+steel+hose+clamp&iar=ima...

But I can definitely think of places with slot-heads on deck of the yachts I have been on, which would be a bitch in swell. And stripping a thread would also suck!