1)离境时,从没交I-94,航空公司也从没问我要过I-94
2)回美,航空公司check-in 时,只是show my Canadian passport, never ask me for US visa.
3) 入关时,show my Canadian passport and I-797A, the officer just took off my old I-94, and staple a new one with date same as on I-797A.
4) My I-94 doesn't have multi-entry stamp on it. The admitted stamp just show H1B and class until.