I reset my data counter and browsed the new 3d maps in iOS 6 on an iPhone.
In 1 single minute, of looking at just a handful of streets in London (some which didn't even download), I had used 22mb of cellular data. Obviously this is something of an eye opener and something most customers are unlikely to be aware of. Circa 100Mb every 4 minutes is really quite horrendous and could see many customers data usage totally wiped out in well under an hour.
The 3d maps on the iPhone is clearly quite revolutionary as well and something of significant curious interest. If people can't wait til they get home to try it, they'll be out of data within their first week.