I thnk there has to be a sense of propotion here. FCUM fans have to accept that there is always a chance that idiots will turn up to their games because of the Manchester United connection, and that because of the large percentage of the local population that follow United, you well inevitably get a higher number of idiots.
Altrincham fans also need to accept that to most people that follow Manchester United, FCUM is not even on the radar and there's always a chance that these trouble makers would not even be aware of Tuesday's game. Now the fixture has been set up it needs to go ahead, but I think if FCUM want to build a reputation as a club for real fans they need to have some of their own stewards at the game so they can identify if any trouble makers are with them or not.
But .. segregate the game, don't allow in fans who are already drunk, and don't allow them in with carrier bags full of booze.