I thought 300 was generous, but it was a quick estimate (count 10 people and use the area they take up to estimate total). Could be some out of the shot too.
The headline in PennLive: “Hundreds stranded outside of Hillary Clinton rally in Harrisburg “.
So they have an excuse out.
With Trump, it is thousands who are waiting to get in LOL.
They probably weren’t stranded outside - they probably started heading for the hills after she started shrieking.