That seems to happening too often. I posted one from Kansas City this week.
The guy that took a fatal dive in KC wasn't tied in to his bucket and apparently was using the bucket to manipulate the branches he was cutting off. That, or a bad cut toppled the branch onto the lift. Either way, the bucket broke off the pivots, pouring the operator out.
When all the crashing was done, the branch was hanging from a rope, the bucket was hanging from it's lines, and the operator was the only thing that made it to the ground.
Guys! Inspect your truck every now and then! It wouldn't hurt if you tried to avoid using it as a crane, too.