h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

..on the other hand is quite easy to come by.

Method:
Get dressed up in a good suit and go out at about 6pm on Friday to a bar in the "business centre" of a city. If you see a large group of people taking up a whole room you have found a "company drinks" session going on and have struck liquid gold. Now go up to about 3 or 4 seperate groups asking stuff like "Have you seen a bag around here", "Have you got the time" etc. whilst also keeping your ear open for the company name. The barstaff will get used to seeing you in the company of these people and then you should go over to the bar and ask "Is the [company name] tab still open?". If yes, order a pint - the barman will assume you are on the company payroll and not charge you...but as you didn't actually say you were your concience is nearly clear.

Note: It's called a "bar tab" where I come from, but its worth checking the local name for the head of the company's card behind the bar ritual

This can also work at Weddings if your party hasn't got a tab going. Especially if the other function room has guests at it that you know. Not that I've tried this *of course*.