[proberts]

Adjudications vary considerably from land crossing to land crossing and from airport in Canada to airport in Canada but as a very general rule, it's easier to get a TN through CBP at a land crossing or airport than through USCIS but this also depends in part on specific TN occupation being applied under and the applicant's background. It's rare but not unheard-of for CBP to deny entry to a Canadian with an approved TN petition. Again, the risk varies by land crossing and airport with Pearson probably the worst and to be avoided if there's any concern.