Colchester and proud!
Director
Firstly - they'll check if you are on the database as previous purchaser (and potentially check how recent/purchase history etc) - if you are then you'll be sold tickets - very easy to code that into on-line sales as rules based. I suspect that at some point (if not already) for new purchasers trying to buy tickets (or maybe more than 1 ticket for example) in certain parts of the ground it won't be processed and you'll have to phone up.
It can't be fool-proof without investing a lot of time on each transaction over the phone but I would imagine that they may choose to do that if patterns of new people emerge trying to buy for this match.
Some will no doubt get tickets, but I seriously doubt that many of your fans will even attempt it - you've got 2000+ tickets and aside from a couple of posters on here suggesting they will try and purchase I'm not sure it will be that significant volumes (despite some protestations that there will be "hundreds" in the home ends)
A few dotted about will not be an issue, the club will just be wanting to avoid large pockets of away fans in home areas. When it comes to it, if away fans are sitting next to home ones and just indudge in the normal matchday chat you tend to have with those sitting next to you, even if the home fans realise they are away supporters nothing will happen and that's how it should be.