Using Bar Codes for Check In and Express Check Out

I'm playing around with bar codes for check in. We'd like to to assign each of our regular parents a key tag to speed up check in/out. Today I set up a test activity and found that check in works great. However, I noticed it still prints a "claim ticket" for the parent and that you can't use the same bar code to check out that is used to check in. Am I missing something?