Was told before my last trip on DL that listing is absolutely required. Getting listed was no problem on a standard DL reservation hotline.
For US departures (domestic in my case) listed stand-by pax were displayed on a screen on the gate and asked to show up on the gate only when their name either changed colour or moved to the "accepted" part of the list. I always got on about 5-10' prior departure when seats of no-show pax were released. Baggage Check-In was normal with SBY tags put on bags.
Very efficient system, not requiring stand-by pax to linger around the gate agent to avoid missing their names being called up.
Expect to be on the veeery end of the list as a non-DL employee, though
