I said it was customary in the sense that that is the normal way we settle this kind of problem in daily life. I did not feel it necessary to elaborate, since it is pretty evident that it's not common practise in relation to elections. It seems to me a fair way to respond to the anger many people would feel if their initial victory was reversed.

Having several votes in a row is of course common practice in many electoral systems - for example in France, where a two stage presidential election has recemtly been followed by a two stage parliamentary election.

Admittedly Brenda from Bristol would be enraged, but it seems to me that putting up with extra votes in order to reach some kind of consensus or at least shared acceptance of the final result would be worth it.