I travel enough to know to include my KTN with the reservation. In this case, I was flying AA and I noticed the TSA Pre symbol was not on the boarding pass. This was pointed out to the check in agent and she asked for my Nexus card to double verify in the system. She re-printed the boarding pass but the TSA Pre logo was still not showing up for whatever reason. Maybe a glitch in the airline computer system? This has happened infrequently in the past. All I needed to do was to present my Nexus at the TSA Pre check point to say the airline was unable to print the TSA Pre logo. The agent would take my Nexus card, put it through the scanner. When it returned with the loud beep, the agent would just wave me through as any competent agent knew Nexus is entitled to TSA Pre. It appears that in this case, the TSA agent did exactly in accordance with the rule, which is fine but its amusing that the TSA agent appeared to trust the airline more than the positive signal of its own scanning verification device. Next time, I shall wait at the check in counter until the airline agent is able to print the TSA logo on the boarding pass. I would suggest everyone experiencing this issue to do the same. On my next leg ex-SFO, the TSA Pre logo was printed on the boarding pass without any problem.