Hmmm...Maybe I am not a very trusting person. But there is no way I would just send my passes to someone I do not know. In the end I am the person who takes responsibility for a person who uses my passes, it is my employee number that is on the pass.
I also know first hand how often passengers that use these passes do not understand that it is stand-by, even if they have been told that. They do not understand when they show up on a Sunday/Monday/Friday to travel non-rev it is not a good ideal. Also, as for my airline, there is no liability on their luggage when a pass is used. Your luggage was lost or damaged?? ..oh well !!
I luv my job, I just can't risk giving my passes to someone I do not know.
I will find other ways to support the troops.

(Also...those passes are normally space available, those soldiers HAVE to be back at a certain time. Can you imagine seeing a soldier that could not get on a flight due to no space...omg..he would be considered AWOL.)

Think about it before you hand over your passes...JMHO