I find that story hard to believe (and I'm one of the "nAAtives" who thinks that the former TW employees were not treated fairly in the previous combination). If you are afraid that something like this will happen to you, then you need to learn how to print out a copy of the standby list; so that you will have a date/time stamp on the hard copy.
If such happens to you then you file a formal complaint with travel services. For those of you who are currently LCC employees, please remember that AA gate agents are non-union. Do you really believe that someone would risk losing their job just to spite former TW employees? Messing with the standby lists is a termination offense for gate agents.
Off an on since the AA-TW combination (and I'm not going to argue with you about whether is was a purchase, a merger, or a ham and cheese sandwich...it was over 10 years ago, that ship has sailed), I have heard stories such as this. When the teller is asked to provide date, time, flight number, city info or anything approaching facts, the story teller then starts saying "Well, it didn't actually happen to me. It happened to a friend of my next door neighbor's, dog groomer's, second cousin."