I would like to do this, as I demo Traveller and Paranoia at RPG shows in the UK whenever I can. Sadly, as I don't have a local games store interested in demos for anything other than CCGs I'll have to pass.
Just think of it this way even if you only do it twice a years at conventions it, builds the Mongoose line by creating players. Who may end up being your neighbors you never new were there. It also helps you to become a better gamer in the eyes of fellow gamers who will thank you for teaching then a new great game.
I currently demo Traveller under the BITS banner (http://www.bitsuk.net/
) and I run Paranoia for the pleasure of seeing happy players get up from the table. I'm planning to run Traveller and 2300AD at Dragonmeet in December, for example (http://www.dragonmeet.co.uk/
Apart from a few teenage children of existing gamers, it's been a long time since I ran games for people who hadn't roleplayed before - but that may be because the roleplaying shows I normally attend don't really attract non-gamers (in the 80s I used to run games at SF conventions where you could count on non-gamers who could be persuaded to try it).
I looked at the MI programme a couple of years ago but as the shows I normally attend are all in the September to March period I couldn't meet the hours requirement throughout the year so I left it.