Standard practice nothing new here.
It's just some DYKWIA pax would run onboard with a blank face avoiding all eye contact with their boarding pass in pockets. Then when you ask to see their pass, they go:
-why?
-again?
-They check everywhere so annoying la!
-DLLM!
-I'm a DM/GO/SL/GR/AM you should know who I am!
-Go deal with it yourself!
-what kind of service is this!?!?!'
Combination or all of the above. True story...