You could put it in a notepad file on your computer, and never need to go to your wallet.
You could google AAA card and use the number off the images that come up, the one from the Amtrak site for example of a sample card is a valid number.
It's pretty funny, at least to me, that you choose not to use them when there are way easier ways to do it.
Some of the hilton chains also require you to enter your AARP number if going for that discount too.
I agree it's a good thing, or else everybody would just check that box, which means the discount is pretty much worthless.