The shadow perfectly lines with the line

They'd be able to see their shadow anywhere on the field though.

I tell the sidelines that. It's hell trying to run the lines without stomping on a two year old or someone's face when they lay down four inches from the line.

If you can see your shadow or I can hit you with my flag you're too close. Not in those words, but that's how I mentally measure and determine when to tell people to back off.

Oh my bad. I thought you meant players.