At least here in Europe it is a general custom to leave cheap tents on site after the festival ends. Many yonger generation fans and teenagers dont fancy carrying their tents back home after the festivities. While you see many more mature people folding their more expensive tent neatly back into the bag.

In the last decade this has become some sort of a plague with lots more stuff other than tents getting left behind. Often getting torched and burned too. Which is just terrible for our environement in multiple ways. 

And all things left behind end up in a big dumpster anyway. A few Dutch people have had it with this "trend". Already last year they have come up with a concept to be able to recycle those leftbehind tents and to reuse them. And apparantly they are waterproof to boot! 
They call it the KarTent

(The most amazing part is the waterproof abilities, but if you consider how much process has been made using nanotech. check this movie: https://www.youtube.com/watch?v=3ayRImPvcQU)

After an initial testing phase last year on some small festivals, the inventors are now looking for bigger challenges. They are trying to convince as many European festivals as possible. Now already 'Best Kept Secret Festival', 'Bospop', 'Promised Land' and 'City of Dance' are on board.

In Belgium organizers are still pretty carefull but positive none the less. 'Daydream Festival', 'Sunrise Festival' and 'Groezrock' will offer the KarTent in their next editions.

After awaiting the results and response the organisers are considering to expand the offering. But according to the Groezrock organizer, people still can opt for the old fashioned tent and will still have the choice between the 2.