I was coming home from Fort Collins today. Nice rain storm in northern Denver, followed by a solid mist from Monument Hill all the way to my place in the Springs.
I could feel my chain needed adjustment on the way home, which was weird because I just adjusted it about 1000 miles ago (chain only has about 7K on it.) Getting on it about a mile from my house, it starts clicking really bad for about 3 seconds, then I heard one loud click, followed by an absolute loss of power. I immediately shut the bike off in case it damaged my cases (it didn't), and coasted into the nearest parking lot.
Chain was still dangling from the chain guard, so I grabbed it and examined it. Still the right length minus the clip on master link.
Looks like rivet style for me from now on...
As for "bet it wasn't maintained" or whatever, I just cleaned and lubed it while I was up in Fort Collins yesterday. The master link was fine, and anyone who wants to examine the chain for signs of abuse is more than welcome to stop by and take a look at it.