Casks and Kegs remain the property of the brewery.
They are not the publicans property to give away irrespective of the length of time the container has been on the pub premises.
If a brewery has ceased to trade the containers will be owned by either the receivers or the new brewery owner.
A company called Kegwatch actively searches and monitors forums etc as well as other outlets in order to track down misappropriated containers.
At around £75 + VAT each they are not a cheap commodity for anyone to lose to theft.
If you accept a container that does not have written transfer of ownership from the brewery stamped on it to yourself you are in receipt of stolen goods and liable to prosecution.
Either buy a re-conditioned one from Close Brewery Rentals ad linked here :
http://siba.co.uk/classifieds/show-ad/?id=2898
or buy a new one from any of the suppliers but don't steal from a brewery.
Sent from my BlackBerry 9900 using Tapatalk