I think using phones to login to Persona would be a bit reckless really. If you guys wanna know about a related (well, sorta) thing that happened here during the elections was that many people used their cellphones to try to commit fraud, as the company who made 'em itself was associated with the cracker who could get into it, so it created a bit of a state of panic amongst people - if you’ve had the crack, you could do it by cellphones - easier said than done, but seeing as this was a really heavy election in here - but justice has been done, thankfully - with a lot of manipulation of the media and anything else the PSDB party could do in their power to win and thus create total chaos here, and what with things not being necessarily safe here in Brazil in no way whatsoever concerning internet security (forget about TOR and anything else; we’re completely exposed here, and well, I know enough to prove it but will keep my big mouth shut over THAT issue in particular) - I don’t even think twice that more advanced countries in terms of technology should be careful.
That said, yeah, I oppose the login into anything related to Mozilla with cellphones. Just an advice. Big bro’s watching…