If the Shoe were on the other Foot
Europeans who use a credit card to buy an airplane ticket to the United States open themselves to further scrutiny by US authorities. Even special food preferences indicated to the airline would be communicated to US law enforcement (i.e. if you order a kosher, vegetarian or halal meal), and those could be the basis for requests for more information. Investigations kicked off by these minor details would concern not only possible ties to terrorism but also anything the US considered criminal activity.
These details, only now revealed to the European public, have provoked a good deal of controversy there.