If we are talking about a player new to the team or the organization, I would have to say that my responsibility to, in order of priority, returning families and other new families, would be to take a pass, of course after really being thorough in an objective determination of how the reputation was earned and what is factual and what is out of context or untrue, I have over the years run into situations in which the poor reputation had more to do with a difference in philosophy than anything else, think about the many times we have watched and heard about athletes given a "change of scenery" and blossoming in the new environment.
I have always tried hard to avoid "visiting the sins of the parent upon the child", and if we made a mistake in choosing a new family, will do everything possible to salvage and avoid the loss of a player because of poor behavior by the parents, however, if they just don't get it and don't seem to want to get it, the responsibility to the other families and players must take precedence, the really unfair thing about all ofthis is we have found ourselves and the others, players and parents, tolerating behavior in a situation in which the player in question was a "rainmaker", I noticed a few posters indicated that with years of experience you learn that even then it is not worth the unpleasantness inherent with a family of this type, that I think is learning from your mistakes.
Good question, and good answers, guess it comes down to what the goals and objectives are for your team, I think any team needs to establish in writing their core philospohies and expectations of teams, coaches, players, and parents, and then make sure EVERYONE knows them and knows they are just not words, that you believe in them and believe that they will make everyones experience on that team or organization a good one, communication with players and families is paramount, many times when you make it very clear what is expected, families that cannot understand and live by these philosophies and expectations just move on.