I'm aware of that, but when it comes down to it, the accountability of any issue that were to arise with those fans wouldn't lie solely at the feet of Rangers. They would, theoretically speaking, have the right to say that Aberdeen have to take some blame as well, as they sold the ticket. In court, they'd have a pretty good case if you ask me. As much as I hate to say it...
Put the boot on the other foot, and let's say that Aberdeen were saying the same to the Old Firm, give us 5% as we sell your tickets. They then tell Aberdeen to get stuffed, and that they'll sell the tickets to Aberdeen fans. Next Aberdeen-Rangers game at Ibrox sees a handful of Aberdeen fans kick-off and cause a bit of trouble in the away end.
Would that be Aberdeen's fault? Would you accept Aberdeen being punished for Rangers selling tickets to moronic fans? I for one couldn't see how Aberdeen would be held accountable.
As I've said already, add the 5% onto the price of the Old Firm fans tickets.