I got my iPhone back from service with a sticker on "WMI Fail" or "VMI Fail". What is "WMI"/"VMI"? I just got my iPhone back from service with a sticker on "WMI Fail".

What is "WMI"?

Googling doesn't return any sensible Apple related explanation, neither does asking @AppleSupport on Twitter (they didn't know).
By coincidence I met someone who works with this and he told that WMI was an acronym for Warranty Mechanical Inspection. He was "pretty" sure about this although but not completely sure (first he misunderstood me and thought I said VMI which he explained as Visual Mechanical Inspection - I guess "Mechanical Inspection" for MI is a safe bet at least).

If someone could confirm/refute this it would be great.