Once I went to meet my frnd @ Gwalior station. He was travelling by Chennai Rajdhani 2nd AC. A1 coach didn't had anyone alighting or boarding the train so TTE straightaway checked with me if I'm the genuine traveler or not and didn't allowed me to board even for a min to meet my frnd.
I think they have fair idea about partially WL tickets and accordingly deal with WL passengers at the boarding station itself to avoid any mess during journey.