SpaceX would face an FAA investigation if a mishap occurs during a landing attempt (whether on land or at sea) because the FAA is responsible for ensuring the safety and compliance of all commercial space launches and reentries in the United States.
Even though landing at sea is a unique SpaceX capability, the location or method of landing doesn’t change the FAA's oversight role.
If SpaceX landings start to fail, what is to say that the next one goes more awry and lands on a home in Cape Canaveral? They do land landings sometimes and we don’t want that to happen.
Like you sort of imply, it seems they are being held accountable for being better but still if they provide any capability it has to be done safely.
