See, I'm actually opposite--I always ask for a booth because I feel like I'm hiding in them instead of out in the open at a table for the whole restaurant to stare at. I guess i'm not quite big enough to have the problem of not being able to fit, so that would be why I feel safer in a booth (on the inside against the wall, too). When I was a hostess, I made the same blundering mistake several times--seating larger people at, say, a two-person booth. They would have to pointedly ask to move and I felt terrible each time. Of course, I state for the record that I was a simply lousy hostess, definitely not insensitive. I'm afraid sometimes people just don't consider the aspects of a situation that aren't immediately apparent to them.
Sorry you went through that