Last night I had reservations for 8pm, but for some reason Opentable registered it to their computer as 6.30. So when we showed up, there was no table available. I definitely made a reso for 8, because they sent me a confirmation email with that time. The hostess explained that this had happened before, when Opentable inexplicably used a different time than the one it showed on the screen. Luckily they had room at 8:30, so the damage was minimal, but if I had reserved for a Friday night, our evening probably would have been ruined. One of my dining companions last night said that this had happened to him before as well -- Opentable assigned him a completely different evening.
What the heck is going on? How often does this happen, and how long as this been going on? That's bad enough to make me reserve on the phone, every single time.