I have a coworker who had an interview with another company. He brought back their salary offer to my boss and received a raise to match that offer. Now, I hear the coworker bragging that it was only a bluff, he was never offered the other job. I am wondering how competitive salary offers have worked for other people. Should my boss have requested something in writing to verify he had the offer? Is it "fair" to bluff like my coworker did? I am curious how other situations of competitive offers have worked for folks.