One reader suggested the idea of calling Delta (and some of the other companies listed here as well) to book a reservation and as an afterthought asking, “Do you still offer a discount to NRA members?” When the answer is “No,” just politely say, “Oh, never mind, I’ll use a different airline.” Statistics have shown that only a dozen complaints of any type cause companies to review the problem.
http://www.dcclothesline.com/2018/03/04/delta-airlines-other-companies-crashing-burning-due-to-nra-boycott/