We had all the documents, but the issue was zero interest to talk to a wierd foreigner! So I never got to show the docs. I know that slow Italian works as a half reasonable comms method to Spanish as it worked very well in Peru, even got permission from the Alcalde of Aguascalientes to bathe Machu Picchu in microwaves for a year, or at least I think he agreed :-)
I already own lotsa 'blank' re-programmable SIMs for my GSM openBTS, so I didn't even need a SIM, they could've just written my Movistar Ki down on a post-it note & that would've been fine with me.
I'll spend the €5 at the Crossroads ipermercado on my next visit, €1.21/100MB/day is better than my current EU €3/day. ( and is slightly cheaper than a fruity Air-pad2 )