Should I bring my globalEntry card with me when arriving by air ?

I have friends who got flagged by the system in LAX, ORD and DEN , and were asked by officers to show passports AND global entry cards , since they thought those cards are just for land and sea ports , they did not bring them and got kicked out into the long normal line , and one was even pulled into secondary (and yes they WERE members , all US citizens). Although I have crossed the border without card many times and the government says it’s not required for air travel . Should I bring it ? I’m afraid I might lose it if I do.