The Next Web reports another case of post-holiday roaming data bill-shock. In this case a T-Mobile customer wasn't aware roaming data was enabled (although he knew he didn't want to use it) and returned to the UK after 10 days to find a bill for £1200.
As usual, the article and commenters note the European Union and mobile operator's policies to place caps on roaming bills to prevent this kind of nasty surprise, but - whilst roaming costs are slowly reducing thanks both to increasing competition and regulators - the real issue remains here that overseas billing is still not real-time. Mobile networks with roaming agreements can take days or even weeks to settle bills for roaming customers and in that time any caps applied by the 'home' network remain ineffective.
What's needed is full real-time billing between roaming partners. With this in place customers stand a chance of getting warnings (and / or service cut-offs) when things go wrong. Ironically the GSMA has gone some way to address this with a 'near real-time' system (ironically introduced to address fraud... it seems customers needs aren't the top priority here) which operates with 'up to' a 4hr lag. That might help with billing for calls (the source of most roaming fraud), but with data charges in some countries exceeding £5 per megabyte bills of hundreds of pounds can still easily be achieved in that time.
Only full, real-time billing for all services stands a chance of preventing roaming bill-shock and - until it's rolled-out - operators should offer to disable data in countries where it's not implemented.