Unshucked Oysters in Crawfish boil

This weekend I was told of people putting a sack of oysters in the crawfish pot after they pull out the crawfish. They said they oysters open up and they soak up the flavor from the boil.

I did a little research and I saw two mentions of this and each person had slightly different methods.

The first said you have to put them in cold water, bring them to a boil for 10 minuets, and then let them soak for 20. this person said that if you put them in hot the oysters will seal shut and not absorb any flavor.

The second method is similar to what I was told. They said to dump the oysters in the strainer after you pull the crawfish and boil for 10 minuets. The water is still hot when you put them in.

So, has anyone done this? any pointers or advice? Do you think the oysters would actually seal shut if you dump them in hot water? the hot water method is what I was wanting to try since it would be the easiest and quickest.