My son flew out of YYZ for a two week vacation in Scotland in June. He found some reasonable priced long term parking near the terminal. Drove from Michigan to Toronto. At the border he was asked a few questions...why (cheap flights)...who's car (mom and dad's)...where you going to park (he had a print out of the place from his internet search, including the $10 off coupon). Bottom line is no problem for a short stay. As I understand the rules, it's actually 6 months before it's a customs issue.