Is there a relative component to the evaluation of genericisation? eg., if only truck drivers know about the term Waterluvian, but the vast majority use it in the generic way, then it's generic? Because it would be a relevant update to that law, & apply here
Because there's not actual written legislation, you could try to make this argument in court, but, previously courts have stuck to the idea that they mean everybody so truck drivers wouldn't be enough. Maybe "Everybody in New York" cuts it in a New York court, certainly I'd expect that "Nigerians don't know this word" wouldn't count against you in any court in the United States of America - but the sort of relativity you're thinking of was definitely not on their mind.
