Just like I thought. I have crossed into canada by land & air, and never has my I-94 been requested (or demanded) by any one.
I believe there is a process where the airline would take the I-94, but it might be voluntary on the i-94 holder. This creates a loophole which the OP's wife could say she gave back the i-94 and it might have been misplaced by the airlines, and the US consulate officer has no way of proving that OP's wife overstayed.
I believe there is a process where the airline would take the I-94, but it might be voluntary on the i-94 holder. This creates a loophole which the OP's wife could say she gave back the i-94 and it might have been misplaced by the airlines, and the US consulate officer has no way of proving that OP's wife overstayed.