I don't buy the part of the story where they resolve the situation by letting him keep the SG if he signs a liability release. A release signed by a minor (17 years old) isn't worth the paper it's printed on. If the Who's people were sharp enough to even have releases on hand, I'd think they would be aware that a minor cannot legally enter into a binding contract such as a release of liability.
Now let me tell you about my '61 Strat that was given to me one night at a Doggie Diner by Eric Clapton himself. It was 1970. I was 15 years old, eating my hot dog, minding my own business, when Eric Clapton comes up to me and asked to borrow a couple of bucks for a dog and coke. I gave it to him. To show his appreciation he told me that he had this old guitar that was given to him by Jerry Garcia and he was a little too tired at the moment to carry it around, so he gave it to me! I've had it ever since. Now I'm willing to sell it for only $500,000. That's a cheap price for a Garcia/Clapton Strat. The buyer will also receive a picture of a Doggie Diner Dog statue (just like the one that stood outside that Doggie Diner, lo those many years ago), and a letter of provenance confirming that I am the actual writer of the letter of provenance. Here's your chance. And if you buy in the next 24 hours, I'll throw in a free veg-a-matic. It slices and dices like nothing you've ever seen! Free shipping too! Such a deal!
Bill, tgo