I have been recently working outside my home country and I disable my mobile data as soon as I reach the airport.
My Nexus 5, now with 4.4.3 reports 0 bytes of data when I am in roaming and I never got a notification or any sort of activity that may point to a data access being made, yet my service provider sent a big bill with many 10KB accesses during the time I was in roaming.
The same problem might exist while at my home country, but since I have a few hundreds of MB to use each month, I can't really tell.
Anyone else is facing the same problem?
I will temporarily ask my service provider to block my data access while in roaming, but I would like to understand if that is some sort of Android bug or a service provider charging what it shouldn't.