Bump Draft/Pushing

[jjordan]

After a serious accident this past weekend at Road America the subject of pushing/bump drafting has heated up considerably over on this side of the pond. I can not say that the accident at RA even had anything to do with pushing (and bumping and bump drafting are 2 different things to me.), but just wondering how much of this (pushing in a draft) is tolerated where you race AND if it is NOT tolerated, how is it policed/punished?
The majority of opinion I have heard this week is that it should not be tolerated but that the only effective way to police this is by the racers policing themselves, by agreeing beforehand not to do it. Does this work or is there some better way to insure compliance that we are overlooking? Looking for some fresh insight on this subject. I'm no angel, I have been guilty of pushing, when 2 guys get hooked up nose to tail and they go by you at 6-8 MPH faster than you can go by yourself, it's pretty hard not to get on the train. The only really effective rules are the ones that are easy to enforce, so let's hear your input on how this is enforced in your area or is it just tolerated?