I've stayed at moderate resorts many times, and have never had any problems with people pushing and shoving to get on to a park bus.
Btw, there are not lines at moderate or deluxe bus stops. Some people do stand by where the bus usually stops, but there is no line for each park. Most people kind of mill around, or actually sit on the benches, relaxing. A strange concept, I know!

Even so, I have never been shoved aside and ended up missing the bus that I needed. The vast majority of people are just not that rude.