It's your choice if you want to show your ID or not. I prefer not to as part of my identity protection.

The merchant pays for the loss.

If you have retinal scan, why should you need to show additional ID?

>So we should help people use stolen cards by not showing proper identification?
>
>Who then pays for the damages? Some magical being? The government? The bad old bank? MY INTEREST RATE perhaps?
>
>They ought to require fingerprints or take retinal scans along with a picture ID IMHO.