I suspect it looks worse on TV than on the pitch. I doubt if the match ref has much say in this at that level. Oh and if he had made Ireland change to their normal strip it would have been green against green )
Remember France V England that night when the pitch was frozen and both teams and all the official and TV companies were ok to play, and Dave Peadson, the ref, called off the game.
The ref could make them change shirts
Was it just me or did Coenie Oosthuizen look well pissed off at the medic who lifted his knackered leg from off the medical bag as he (CO) lay on the stretcher/cart prior to being carried off at the Aviva.
It's come up a few times in high level club games and the excuse there was that they'd decided well in advance (months) that whichever team would play in a change of shirt, but between then and the match they'd got a new kit.
Apparently this sequence of events is fairly normal and only occasionally do the shirts change enough for it to be a problem.