Andy_Langton - 10:37 am on Feb 13, 2013 (gmt 0)
Are the general public ready to connect their card number to a SNS account?
In the UK at least, Amex are already doing this with Foursquare, and offering pretty large paybacks for doing so (e.g. you check in/eat at a restaurant and they give you £15). These are very popular offers.
So I'd say given the right incentive, Joe Public's unease disappears pretty quickly!