Why are green bottle less favoured?

MBT (3-methyl-2-butene-1-thiol) happens real quick. People have reported Heineken bottles skunking when in direct sunlight in less than 15 minutes. Heineken has a minor defense of green tinted bottles, clear obviously has less. An hour in an ice bucket outside would most certainly skunk any beer in a green or clear bottle. Since MBT is caused primarily by hops in the beer, the more hops used, the greater the skunking.

In order to prevent skunking, keep all bottles (including brown) out of direct sunlight and fluorescent light. Exposure to incandescent lighting needs to be minimized as well, but it takes longer. If you have old boxes from beer runs, don't throw them out, re-purpose them for keeping your bottles in. A closet or cellar works well to help with preventing exposure as well. If you need to store fermentation vessels, shirts work well, pulled over the top of them.

When transferring from storage to the beer fridge, minimize exposure as well. If green or clear, make sure they're concealed in UV-impenetrable containers from the cellar/closet to the beer fridge.

I store mine in cardboard boxes. I use lots and lots of clear bottles, and a few green ones. I don't worry about skunking at all.

Sometimes I'll lightly skunk a pilsner-ish beer on purpose. I do that with 20-30 minutes in direct sunlight (in a clear or green bottle).

But accidental skunking just doesn't happen to my beer.

I store my bottles in the closet, and then move them to the fridge when I'm ready to chill them for drinking.

I salvaged several green Becks bottles that I use for bottling, and of course, I've never had any issues. I do feel weird when I get stuck bottling a dark beer into the green bottles, but that's obviously just a mental thing.

To answer your question, though, the answer is (much to my surprise) possibly yes, an hour in the ice bucket at the BBQ might skunk your beer. I was curious about how fast skunking might happen, so I did some poking around and found this post, which is consistent with several other anecdotes on the subject.

http://www.homebrewersassociation.org/forum/index.php?PHPSESSIONID=d08882783185c6ee3e6cb16b86b3b59e&topic=4876.msg57156#msg57156