This happens to me all the time. It's almost not fair to all the guys who have to use e-bay and craigs list. I got a just about mint Jonsered 90 this way, and it drove a buddy of mine nuts because he had been looking for a nice one for 20 years. He kept offering to buy or trade for it, but I just gave it to him for Christmas.
A lot of guys also walk away from toasted saws because they would rather buy a new one than do a rebuild. But parts at cost plus my own time is a lot different than list plus an hour labor. If the saw is really nice cosmetically, then it's hard to resist the temptation to do it over. I have an absolutely mint 630super that way.
But Thall's story also illustrates that to some people, saws are just junk taking up space in the garage, and they see no value in them. A logger friend of mine got a nice 028, and a hardly ever used 272XP for free from his neighbor. The neighbor said that he wasn't going to cut wood any more and he was tired of stepping over them.
Hey, all saws should go to a good home where they will be appreciated, right?