回複：Did the airport check I94?

Airline employees are instructed to take back the I-94 for outbound (of USA) passengers and send I-94s to local CBP custom and border office for data entry. Airlines employees themselves don't care about whether I-94 is expired or not. CBP and BICE (and later after data into computer system, USCIS, DOS, US consulates) will be the ones that care.