The inevitable EULA
that you have to read (all 500+ pages) before they will license you to drink a pint.
They will be along later to collect the same amount of urine because the EULA only allowed you an 18 hour loan of the liquid.
Failure to give up the urine will lead to a law suit being filed before you can blink an eye. They will allege IP theft, wilful patent violation(triple damages) and anything else that the $1000/hour lawyers can think of.
Sadly, I'll be in Haggis land when the GBBF is on but I hear that the Isle of Skye brewery in Uig brews a pretty decent pint.