Sleeping in cars, having consumed enough alcohol to be over the limit to drive.
Some years ago, I enquired at Alder Hey Police Station on whether I could be breathalysed/banned if I slept overnight at Maghull Town Hall carpark after the annual Folk Day.
The fiendly bobby advised that it would be difficult for the law to prove 'intention to drive', even with the keys in my possession - if I had all the seats down & was all ensconced in my sleeping bag.