Carpool to cross border and catch flight at US Airport
 

I'm in Winnipeg and may take the offer of carpooling with my friend and her family crossing the US border and catching our flights to US destinations. I may book 2 separate one-way flights to save money. I'm going to Dallas TX while my friend and her family are flying to LAX. We're both going on vacations and I've got a Mavericks and Stars game tickets. They are going to park their car in Grand Forks. Later on, I'll be flying home back to YWG while my friends will fly to Grand Forks and then make the drive back up to Canada.
Is it possible be denied or experience extra scrutiny at the US border because I'm taking the flight back home and not riding with them? I'm sure they keep a record of the number of passengers in the car crossing into the borders. I don't want the border staff to think my friends are transporting illegals since there will be 1 less in the car upon the return to Canada.

Expect a few extra questions but other than that I don't see an issue. Just don't use the word carpool. Friends is ok to use :)

If you are buying the return flight to YWG before you leave for the trip, simply show them your tickets. The rule about not answering questions not asked might also come into play here.

I disagree. The other people are acquaintances that you are ridesharing. If they have drugs or criminal links, the last thing you want is to be their friend and Co-conspirator.

Well if you don't know the people then you should not share a car with them period. I have gone over the border with a friend before but I have no concerns over illicit cargo.