[jacquesm]

There is plenty of anti-competitive in the real world (phone companies are a nice example, but Intel and Microsoft have a nice track record too), but in this particular case due to the nature of the material involved it would be extremely hard to collude in the first place and almost impossible to prove that it actually happened if it did.

A bunch of guys having dinner and talking over business is not collusion, they call it 'synergy'.

Collusion is: "Start-ups X, Y and Z suddenly found that none of the angels present at such and such a dinner would accept deals over <some value> or under <some conditions>."

And even then you'd have a very hard time proving that it was because they colluded.

Also, how long would it take one of these guys to figure out that if he 'broke' the rule just once that nobody could ever accuse him/her of it and he'd have a surefire winner because that start-up would have found doors closed everywhere else.

It simply isn't going to happen, the VC world (especially angel investments) is too competitive (not in the last place due to YC) and too closely watched to get away with any of this.

[protomyth]

"and almost impossible to prove that it actually happened if it did"

Wouldn't that be the best type of thing to collude on?