You like repeat this in each post you made.
I think the Border Patrol doesn't care about the $ the inadmissible US citizen is spending. They don't want a former drunk driver to possibly drive in Canada.
of course that guy doesn't care, it doesn't mean he shouldn't. people who operate purely from fear are idiots.
if the law/rule is that you don't let someone with a DUI drive into Canada, that's fine. but it's dumb to not let them fly/bus/rail either. the law should be to not let them rent cars after they get here not keep them out completely.