You are preaching to the converted here. I shoot to 2 cards and have on and off site backup
But I disagree about the philosophy of shooting loads and delivering few at a wedding, because it walks you into problems i.e. Aunt Maud, or the Brides Mother WILL remember you took a photograph of her and expect to see it. Secondly, it wastes a lot of time at the wedding, and a lot of time after the wedding. Thirdly, some of that time inst my own to waste, it is the bride and grooms or the guests.
I have always said I shoot group shots four or five times because of the blinking issue. At something as important as a wedding I don't subscribe to the shoot and hope philosophy. As a wedding photographer you are being employed to get the shot right first time every time. For some shots, you will only get one chance to get them right - first kiss, ring exchange, walking down the aisle, bouquet toss, cake cutting, fireworks, a lot of moments in the speaches etc.. This is especially true if you are a photographer that doesn't do false set up shots.
I do know things have changed since the film days, but in those days, the photographer shot 11, and come back in the evening and shot the last one on the roll, and then delivered an album of 12... things have evolved a lot, but I personally don't get the whole idea of shooting at a ratio of nearly 1:10 or 1:5 keepers.