If I exit the parking lot and re-enter the same day, do I have to pay the parking fee again?

You get a parking pass for the day. So you should have no problem on reentry.

You shouldn't have to! Not entirely sure though! It says it is a day rate so they give you a pass I believe. I have a season pass so my general parking is limited. Free parking with a season pass. Come and go as you please! It's worth it!

You can re enter with your receipt from that day