...really means "Left in / around mailbox". Why does UPS tolerate / encourage their drivers to lie about where packages were left? Well, it's illegal for them to stick it in the mailbox, so "Met Customer" (when they didn't) is the euphemism they apparently use. I'd've been upset if this envelope yesterday had gotten lost ($100000 check from my 401K for funding the final stages of my house renovation). But I had it happen a few weeks ago too, and that time it was hiding in the mailbox newspaper tube (which I've never used so never check).