We also have never had any problems at the Ambassador bridge, they always ask how much cash we're carrying,no problems, my understanding is they want to see us(Canadians)going south with adequate money in out pockets. I think if you have all the answers ready and your documentation in hand don't wear sunglasses or a hat all should be good-to-go. It's late fall and they see an older couple in their huge pick-up with their mobile condo in tow and they know exactly what's going on and I've found the customs officers at the bridge to be extremely polite and courteous, there just doing their jobs.