I wouldn't say it served her right--that's a bit mean! It's not like models are given to complaining to OSHA about hazardous working conditions, but this has happened before. Chloe Sevigney wiped out a few months ago and got a couple of teeth knocked out when she hit the floor.
I would say that the shoes Tiiu was given weren't terribly safe. I mean, if she couldn't walk safely in them down a flat, even runway, then imagine what hazards they'd be to an ordinary woman walking down the sidewalk.
I feel bad for the woman. That had to be seriously embarrasing, plus she's probably got a couple of bruises on her from the fall. I'm sure she'll be just fine, but still, that had to really suck at the time.