Gregg, my experience has taught me that you have to get to a good sale early.
If someone starts pushing and shoving I do not have any qualms if their feet accidentally get tangled causing them to trip.
Sometimes a loud "excuse me, could you keep your hands off of me!" might get them asked to behave or leave.
Professional estate sale organizers usually keep things like that under control. It is the amateurs and such that can end up turning into mayhem.
My brother on the other hand often waits to the last day and last hour. He is looking for stuff they want to get rid of cheap. He buys to resell. He often goes to the same sale at the beginning for the quality items and then returns at the end if he feels it might be leftovers.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)