I live in the US, a relative lives in Mexico. When my relative applied for his SENTRI (Secure Electronic Network for Travelers Rapid Inspection) the online form only allowed US addresses so he used mine. They sent me his SENTRI and I'm trying to give it to him. Is it legal to send it over mail/fedex/ups?
I couldn't find information online about it. Sending sensitive documents by mail is always delicate and the current immigration tension between the two countries make me hesitate.