I spent the first half of my life accumulating assets and I'm spending the second half of my life protecting them.
If you have a home and a pool, you should extend your homeowner's policy to the maximum liability. That extension is the least expensive liability insurance you can buy. You should do the same for your auto policy. Again, inexpensive protection.
If you have significant assets (more than your vehicles, your home and the stuff in your home) an "umbrella" liability policy is essential. It will protect you from all the things for which you're not specifically insured and extend the liability for the things for which you are insured. It's not expensive. You should have at least enough umbrella limit to cover your assets. 15-20% of Americans have more than a million dollars worth of assets. Law suit claims are getting larger every year. So, 3, 5 and 7 million dollar umbrella policies are common.
As to kids in my pool: No one visits the premises without my personal invitation. My kids (teenagers) don't invite others on their own because it's not their property. It's their home (only because I provide it for them). The last thing I want my home to be is "the one house in the neighborhood where all the kids want to hang out." If I have guests (any age) they will be here at the pleasure of the owner. It's important you be cautious and prudent, eventhough adequately insured. One liability claim for a drowned or injured kid can mean you can't get liability insurance, again, at any reasonable price.
Bottom line, NWMNMom's advice; "Depending on the state, waivers mean little or nothing if something actually happens. Get insured, secure the property and excersise your best judgment on just who and how many go in the pool. And cross your fingers" is the best advice in a nutshell.