Yes, twatty, I wasn't parked at any point and there were no signs informing me that by entering I was liable to pay, whether parked or not, unless I left within 10 minutes. My thoughts when queuing were about getting out at some point in my life, finding a space, finding another carpark (big unfamiliar city), getting something to eat for me and my two kids before attending an event we had tickets for. Honestly, panic began to set in towards the end as it seemed like we would never get out and would miss our event (we didn't, but it started to feel like we would). It was cramped with lots of very tight corners, lots of the queueing was on slopes, going up & down. It was just a horrible, vile experience, even without the sodding fine.
At no point did I think 'Oh, I must pay for this before we leave,' and if I had I couldn't have because I was on my own with two small kids in a very slow moving queue so I couldn't have left my vehicle to go to the ticket machine and I very much doubt there's a person on this planet to whom it would have occurred to do so. After finally parking elsewhere, was I going to trek back and pay for non-existent parking, dragging my increasingly fractious kids with me using up the limited time I had left to find my way on foot to somewhere I had just driven by car following a SATNAV? No. Again, no one would have.
Did I ever have the chance to pay £2 but stubbornly thought 'No, I'm not paying that, damn it!'? No. The first time I knew I owed any money was when the £50 fine came through. If I could magically have avoided all this by paying £2 I would have but it was never an option.
Perhaps I should have foreseen this happening once I'd been in there a while, but I didn't. It's changed me a bit though because I've become quite obsessive about checking signs/looking for cameras in unfamiliar places I drive into. It's not really a nice feeling.