We went to Niagara Falls 2 years ago, so after 9/11, and they barely stopped our car. They asked us where we lived, where we were going and that's it. No IDs, nothing. Coming back through was the same way. Some cars were pulled over and customs officials were going through their trunks and luggage. I guess our mini-van filled with juice boxes and McDonald's bags wasn't on their list that day.
Even though it was nice not to get stuck there, I would have felt a bit more comfortable if they did some kind of inspection.