Knutsford plods are very suscpicious by nature. I was mugged there in 1996, and relieved of a pot of 1 coins. The plod, upon hearing my take, seemed to want me to tell about my ENTIRE TRIP, even though this was irrelevant up to the point where I first came into contact with the con merchant who set me up at the previous services. They were more interested in finding a drugs related explanation as opposed to the glaringly obvious one that the muggers saw my prowess at the machines and thought up a way to get some of it for themselves.
No doubt they spent 2 days scouring the CCTV footage looking for something to charge you with, as they could not believe that 4000 could be won from simply playing the game.
People with that amout of coinage are usually "rodding" the machines. (A method for forcing the hopper to give out it's contents by mechanical manipulation), defrauding the changers (recent scam), or simply breaking the locks on the cash box.
36 hours is the most you could have been held without charge, they must have been gutted to have had to release you
It is unusual to get caught at a Motorway Services though, unless you are doing something that looks rather shady. You didn't have a big bag with you all the time by any chance, this is a dead giveaway to security as the Motorway "drifters" travel like this, and they often rob the machines when they get the chance (they don't usually have their own transport - another dead giveaway!)
