Originally Posted by
Eastbay1K
Mexico has no formal exit procedure. Your transit card (lower part of the form returned to you) will be collected at the LHR departure gate.
Is that just for in-transit? Some airports, such as MID, have a formal exit desk where you hand in the card, get stamped, and they can (and sometimes do) ask a few questions. What constitutes formal in this case? Thanks for your time.