Looks like this trick still works in the UK, as people are sending bricks and other flotsam to the UKIP's freepost address.

http://www.buzzfeed.com/jimwaterson/people-are-wasting-ukips...

And in Utah, 80,000 bricks were sent through the mail to build a bank.

http://www.stampsofdistinction.com/2008/07/bank-that-was-sen...