At the Calgary Folk Festival they call them tarpies. Basically it works this way. People claim their space in front of the stage by laying down a tarp. It can only be so big but once you have claimed your spot. It is yours. No lawn chairs allowed but you can use "concert chairs"
I was amazed this afternoon, hours before the gates opened, people were lined up. Lots of people were lined up in the 30 degree plus sun to claim their spots. Mid evening I ducked out to take my camera back to the hotel and the tarpies lineup for the next day was already started.
They even raffle what they call the Golden Tarp. Front and centre, the best tarp spot possible for next year's festival