We've seen a few of them. Apparently some of those packing and mailing chain stores were selling them. After researching a little bit, we determined that they actually asked for some good source documents - birth certificate, voter ID card (a good Mexican ID), etc. when issuing the cards.
We will not accept them, but point out to the person presenting them that the information they gave the mailbox place would be what a government agency (either in Mexico or the US) would ask for to issue a valid ID - and to get one of those and come back to us.
Seemed that the word got around pretty fast in our border communities - we haven't seen one in a while.
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Opinions my own.