Sluggerdog, CO2 comes out at warm temps, you chill the bottle to try to minimise the amount of CO2 that comes out of solution. Like pouring beer in to a warm glass or even opening a bottle of warm beer, foams because the CO2 wants to get out of solution, by keeping it cold the CO2 remain. Aggitation will also drive CO2 out of solution too, that's why you fill the bottle at low pressures to try and minimise the aggitation which leads to foam.
FWIW it's the combination of a warmish glass and the aggitation that gives you the head on your beer. This is also part of the reason that you shouldn't store you glasses in the fridge/freezer-well not if you like a good head on your beer (and if your beer will hold a good head, unlike most comercial sugar beers, why wouldn't you want one). Sometimes if you freeze your glass then pour in the beer it will foam like crazy, this as far as I know is due to the ice crystals that have formed on the inside of the beer glass (frozen condensation) and are creating nucleation sites for the gas to come out of solution (basically creates rough patches that aggitate the beer as it passes). I could be wrong but this was my understanding.
Boil42, I agree that you'd get heckled something fierce, they look like baby's bottle teats.
Cheers, JD
