I've had them take the pass no questions asked, sometimes ask me to sign the back of the pass, sometimes not, and sometimes want to see a boarding pass. Last time I innocently wondered "Why do you need to see the boarding pass?" and got kind of a mealy mouth answer - so they could monitor my flight and update me. No way do I believe that.

I legitimately have passes, but I have also bought more on ebay when traveling with several people I wanted to bring in. It would be pretty awful to be embarrassed by a dragon in a situation like that, or have that happen to anyone you gave passes to.