This isn't so much a "how do I do this" question as it is a "real world ramifications of a design decision" question.
I noticed today that, when using Google Wallet for a payment, when one goes to pay for the service it is possible to see a payment method option as disabled and flagged as "declined" even before choosing that method.
A useful feature, to be sure, but I worry about the ramifications of this from the perspective of the systems on my bank's end.
I can only assume that this is implemented by simply pre-authorizing the payment on each saved account prior to showing me my options.
For those of you who have written banking software, do you know of any specific effects this feature my have on a user's account? What about the potential effects on this system as a whole?
Also, I'm sure that since the release of this product (or at least this specific feature), the feature itself has almost certainly created an additional load on the "middle man" systems in this scenario that may not otherwise be there.
Ultimately, this is my question: Is adding a feature that can have ramifications beyond the direct experience with the software really a good design decision?