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Thanks guys. There's just something odd about the whole thing. The company-who-apparently-cannot-be-named did have clear signs up, so no problem with that. The problem was that that the business whose car park it was had a 2.5 hour event on, and because there was no way to pay for extra time over the free 2 hours, they were telling drivers it was fine and monitoring wasn't operational that day. Forgive me for being cynical, but one has to wonder why that mis-information was being given out.