That's the upshot of lawyer Angela Walsh's court victory against T-Mobile, which has now merged with Orange and become Everything Everywhere.
Walsh, a litigation partner at City firm Abrahams Dresden, will receive more than £500 of data roaming charges from T-Mobile after arguing in court that the network operator had failed to inform her that her new phone could download data while she was overseas.
The charges accumulated during a trip to Australia that Walsh took soon after being persuaded to stay with T-Mobile with an upgraded handset.
Data roaming capability was never discussed during the call, and so Walsh did not know she should take steps to prevent her phone downloading data while she was abroad.
When she returned, however, she found that T-Mobile had disconnected her phone and wanted her to pay more than £500.
These are the charges that will now be reimbursed after Judge Monty Trent ruled that the conversation on the phone between Walsh and T-Mobile had concluded the contract between them, meaning that terms and conditions should have been agreed then.
But despite it describing this as an isolated case, Walsh is far from the only traveller to be shocked by a huge mobile phone bill on returning to the UK.
Back in March 2008, for example, The Sunday Times reported on a City executive who received an £11,000 Vodafone bill after a download of four episodes of the sitcom Friends continued automatically while he was working away in Germany.
And more recently, Anne Roberts from Devon was hit with a £27,000 Orange bill after buying a £20 pay-as-you-go phone while on holiday in South Wales (although this was due to a technical glitch that caused the mobile operator to charge her account 792 times).
Walsh's win will undoubtedly please anyone who has been caught out in the same way, and will give hope to many that their efforts to reduce their data roaming bills will not be in vain.