[hussong]

I agree that iOS and apps could do more to help users stay within the limits of their data plan. Sometimes it seems like they assume data is free.

I once had Spotify eat my entire data for the month in a few hours because wifi was spotty and it just went on to stream (in max quality) over 3G.

Another issue, especially in Europe, is international roaming. When you're near a border, your device may be roaming in the neighboring countries network because their signal is stronger, so you really have to catch the "welcome to foo network" sms and turn off data roaming (or pay for an "EU Day Pack").