I saw the thread about the confusing boarding process for the Coast Starlight in Seattle (involving checking in at a desk, and then lining up to wait to board the train, and I intensely dislike long lines at NYP, WAS and elsewhere (waiting in line to have your ticket inspected as you walk towards the tracks).

Question: what happens if you just get your ticket from a kiosk (or already have it) and just bypass the whole boarding line and just get right on the train?

So often you can just walk around the line and the door to the platform, such as boarding through the lower level at NYP or walking through an open door to another track. Are there any consequences?

For example, I was surprised to see some TSA agents parked on the platform at Greenville, SC; I just walked around them and went up to the train. Nothing happened. Is that always the result?