It's definitely interesting, but my gut reaction is that it is a bad idea. If you invited somebody, that means (a) you know them somehow and (b) you want them to participate in the community. Unless you have a stronger bond with the community and are willing to risk your relationship with the invitee for it, moderation will be quite lax, I fear.
On the other hand, having the inviter sanctioned if the invitee misbehaves is also an interesting concept. The behavior in the community will probably be better, but people will be very cautious to invite someone, possibly starving the community.