Urban ledgend for the Air Force for sure, no Idea about the other services, but I am pretty sure that is false also.

We talk to other services and ask them when we all deploy together and they always think we had the cards which is complete bull crap, and they deny it also so its probably not true one bit.

Now it is kinda true in aircrew POW training, this trianing they litterly beat the living crap out of you and just suposed to take it and bite you lip. Now sometimes people get mad and try to fight back or get way overstressed, then the instructor ceses training for a moment called "acidemic timeout" where they tell you what you are doing wrong. After the time out then they start right back into beating you up.