No service when abroad....
On a similar but somewhat separate issue, I was getting the No Service alert when abroad.
I live in Ireland on Vodafone and when I went abroad to Dubai the phone was working perfectly on the local network then after turning it off one night I turned it back on and there was "no service."
The phone could identify the local networks when selecting settings and then "carrier". But it could not hook up. But then I tried the sim in a Sony Ericsson phone and same thing. One call to Vodafone fixed it. Seems "roaming" had somehow been turned off. I can only guess it was when I turned off data roaming it must have triggered it. The engineers reselected and it was back working again.
Did the same thing in the UK last week, was working fine with Vodafone UK then turned it off while flying to Japan. Landed back in the UK and no service again...I had again turned off Data roaming and the same problem. Again the Phone could identify O2, Vodafone UK, Orange etc etc
So be aware on this especially those on unlocked phones.
And be aware of Data roaming....I have a bill for 350 Euros just from checking E-mail and stocks and weather while in Dubai.....