Think it can't happen here?

Think again.  America just elected a President who is all about attacking "the rich".  

From the UK Telegraph:  Tax hitmen to track your spending.

 Some key quotes from the article:

Credit reference agencies will cross-check details of the income people declare on their tax returns against their spending patterns to identify “high” and “medium” risks of both illegal and legal tax avoidance.

.....

Information will also be routinely shared between the British and American authorities.

....

The Treasury is to provide an extra £77 million a year to HMRC over the next two years to increase its investigative capability. The “affluent unit” which targets the wealthy is to take on 100 extra staff.

This is strictly in Britain, save that "routinely shared" information.  For now.  As this will likely be a model for the Obama Administration.