I don't mind teams wearing "clash" jumpers when facing teams with similar shirts. But I do mind the current "away shirt" trend that has teams changing shirts when at the drop of a hat, when it's not really necessary, just because nike's/ adidas'/ reebok's etc. commercial interests demand it. I remember a recent Portuguese soccer league game in which a team that plays in red shirts played away at a team that wears white ones. Stupidly, the visitors decided to wear their "cream" away kit, and in doing so managed to create a clash where none was before!
As Caveman posted, Footscray's jumper doesn't really clash with those of nearly all the AFL teams. So let's stick to the red-white-and-blue.
French club Bordeaux wore their third kit in home matches on their recent Champions League run.....
They usually wear navy blue with white.
Using your rule, Footscray would wear the away uniform against include Carlton, West Coast, Melbourne, Adelaide and maybe Fremantle. That would give on average 3-4 uses per season.
I must say I don't mind seeing it against the likes of Richmond and Brisbane, but that might be because it's a class kit. If it was rubbish (like the 'Origin' jumper from 2005) then I'd have a different view.