回複：我明白你說的 ：）。 如果是我，我會寫封信問，要不然心裏不踏實。

They had better not take advantage of this kind of the CBP officer's mistake to avoid any potential trouble in the future. Your parents had better visit the CBP local Deferred Inspections Office to fix their I-94.

See this website to find the CBP Deferred office in your area:

http://www.cbp.gov/linkhandler/cgov/toolbox/contacts/deferred_inspection/deferred_inspection_sites.ctt/deferred_inspection_sites.pdf