It's been done before by another chap very succesfully 
http://uk-mkivs.net/forums/t/137003.aspx
I can see what you're saying but if the chap organising it is stupid enough to run off with your money I think there's enough of you to track him down 
100 folk going after him though doesn't guarantee your money back as the other thread you posted about proves

Even Ross Tech was unsure with the first group buy.......... "Don't take this the wrong way, but we don't know you very well. Right now, all we have on you is a Hotmail address. Thus if you make an offer in public, collect a bunch of money from people, and decided to abscond with it, we (Ross-Tech) would end up looking pretty bad. Now I have no reason to believe you would do this, but I really don't want to take the chance of us or our prospective customers getting taken for that kind of money........"
I'm sure it would fine but its the kind of thing you read about in the papers every day and think to yourself, "how stupid can some folk be, sending money to a complete stranger"