Superb stuff Matt

It's always been a bit of a none question as far as I was concerned. My reasoning is this, with heraldry taking a firm root as the 12th C rolled on it was in the interests of a combatant of note to make themselves as visible and as an obvious target for ransom if they were defeated in combat. Thus they might have a hefty bill to pay but they would live.
Also, the Medieval period, for those who could afford it, was very colourful.. Ostentatious shows of wealth were common and garish colour simply made the wealth thing more obvious. Of course, it is unlikely that they would have seen this as garish.