Re: Magna/Sabre Cams et al
Seems a tad late for that now....should've been a recall performed on them a long time ago. There are enough ways around that problem now (no thanks to Honda!) that there's no excuse for owners NOT to perform the mods.
As for the XR's bolts failing, look who's riding them and how. I don't personally know a single person who bought one of those li'l buggers for his/her child to ride! They're fun scoots even if your knees hit the bars

Not that this excuses Honda's apparently using inferior-grade bolts...but how more specific can you get than "Bolts failing"?
ObDisclaimer: I do happen to work at a Honda dealer, in the parts department. Big Red is notorious for saying a problem is not a problem, just ask V4 owners (VFR reg/rec, SabMag cams, I could go on).