I do one-way YYZ-TPA once a year and drive back in someone else's vehicle. The only problem I've had was on my next visit to the U.S. by air when I was asked how long I'd been in the U.S. during my previous trip. The air crossing puts you into their system but a land crossing in someone else's vehicle doesn't let them know that you've left America. Despite making this trip many times, I've only been asked once, the CBP accepted my explanation and it hasn't been a problem since.