"It is unreasonable to conclude that when a person forks over $30 for a one-time transaction they are agreeing to pay a $1200 fee (silently assessed and without additional warning)."
I couldn't agree more. A friend of mine experienced this exact same kind of thing a couple of years ago, when a group of us went down to Boston (from Canada) for some sports action. He worked for a mobile carrier, so he had a business phone, but he ended up using it so much (while we were roaming), that the bill ended up being $3,000. He didn't even use it that much... just for some GPS and quick Google searching. They never warned him about this gouging or anything, and the only reason he got away with it, whereas a normal person wouldn't, is because he worked for a carrier that worked out a deal.
I'd be interested in seeing a follow-up, to see if this guy will actually have to pay that bill. Judging by his wording, he almost seems settled on the fact that he's going to pay it.