Look, I'm sorry this kid died, but "better safe than sorry" is cliche for a reason. If the sign says No Swimming, rather than looking for a loophole that would allow you to "stick it to The Man" and swim anyway, just find somewhere else for you and your kid to swim, where you would have a more reasonable expectation of safety.
"Better safe than sorry," IS cliche for a reason, isn't it! Used all those words, only to reinforce my point in the end.
"No Swimming," doesn't keep people out of water, regardless of whether or not YOU think it ought to. You can hope that it will, but "swimming" means "swimming", not "stay out of the water". Not, "danger". It just means, "Don't swim." Again, specific OR thorough. Warnings have to be one or another. This was neither.
And, because privately-owned property carries with it default culpability, it behooves an establishment to protect themselves and their patrons from a potentially deadly misunderstanding. Better safe than sorry... like all the smarter resorts in the area.
Instead, they were concerned about scaring patrons, so they omitted the very obvious reason for staying out of the water. Bad jujus.
Tort lawyers are already saying that Disney is at fault. They're calling ZOOS an appropriate standard of comparison, if you own a private "habitat" where dangerous animals will be present. Their liability is mitigated by the fact that the animals are local and widespread. That mitigating factor is nullified by the fact that they are purposefully attracting individuals from other regions who can't legally be expected to know. Zoos? Disney doesn't stand a chance if a lawsuit goes to court.
And, no, the kid who died as a result of a drained pool is not the responsibility of the owner. They were not invited, and the owner placed a fence around the pool. These individuals were guests, and there was no fence.
You're newish, so you wouldn't appreciate my familiarity with the law, but you should have some familiarity with law yourself. Especially if you own or plan to own property.
If the family of the boy chooses to sue, they'll walk away with a multi-million dollar judgment (or, more likely, settlement), and Disney will have a new set of signage either way.
The moral of the story? If you own property, state the expectation - or the risk - in no uncertain terms, or block unsafe areas off such that guests must circumvent the the barrier in order to gain access.