I am going back to my country of origin voluntarily after overstaying a F-1 visa(university) from 2007-2015. So I have a few questions about a possible 10-year ban:
1- Have I accumulated any unlawful presence for the purpose of a ban since my I-94 has a D/S stamp? I have never been contacted by immigration all these years, and I've read that the unlawful presence period in a D/S case only starts when you're notified, is that true?
2- Since I came here I had to renew my passport twice at my country's consulate because the previous ones expired, so I'll be going back with my third passport with a different number than the one I entered the US with, does that make any difference for the departure record? Also, when I came here in 2002 they were not yet collecting fingerprints and photograph at the airport. Not sure if that matters.
3- Does it matter if I don't give my I-94 to the airline at the airport when I leave?
4- What about going to Mexico by land and leaving from there, would that work to my advantage since there would be no departure records? Would that be the same as not surrendering my I-94?
In the future I may try to apply for a tourist visa, so I want to avoid the 10-year ban, but I realize my chances are pretty slim.
Thanks for any advice.

