I don't know about this. No one knows which bus the bench-sitters are waiting for or if their whole party is together. The only time we sit on those benches is when we're waiting for a straggler. Otherwise we stand by the yellow line.
Yes, but the buses aren't going to suddenly speed off. I always wait a few seconds or so for people to start getting up off the benches, as they can see what buses are coming - at least they can where I stay at POR - if I have arrived a few minutes before the bus got there.
The OP was talking about people running to the bus stop and disregarding the people who had previously been waiting/sitting, etc.