I was riding home Monday and stopped to peel a layer. I stood to accelerate and when I sat, BOOM! The head snapped of my seatpost! I was OK; the shop refunded me with an apology. Looks to us (LBS and me) like the post didn't have enough epoxy to properly hold the head. This post was only 6 weeks in service.
I switched to a different post; we'll hope for better