Yes, but the problem is, most people who get denied entry aren't even aware of the issue. Also, if you get denied at all, frequently it's after previous trips to Canada with no issues. It works both ways - a Canadian guy I work with was turned away at YYZ a few years ago for a drug conviction in Canada when he was a teenager - in the 1970s. He had entered the US well over 100 times since then, and it wasn't an issue until someone merged a database or something in 2012.

I used to travel with a sales guy - American - who had multiple DUIs in the US. We went to Canada at least a dozen times together, for work, and he had a lot of other trips solo. He continued with a few trips per for for another dozen years. Last year, he was denied entry at YUL because of his DUI. The last DUI was in 1992, and he gets denied in 2013. After dozens of entries into Canada.