Geoff P said / asked

"We did miss season tickets though and the buying of tickets from the TIC was a bit of a mission, (sorry I don't know why someone needs an address when people buy tickets, particularly when there's a queue!)."

I would imagine that the TIC had been asked by organisers to obtain people's addresses, so that they could be included on a mailing list for future festivals. Makes sense, really - not everyone who would be buying tickets would be die-hard fans, who will keep the festival in their diary come-what-may.