Confounding

To the list of things I find confounding about our religion let me add this: Every shabbos morning after the musaf kedusha there is, in our shul, a mass exodus of men going to the alcove to fetch their hats and shtireimals. These men have, for the most part, used a talis to cover their heads until this point, but, for reasons not shared, following kedusha this mode of covering is no longer acceptable. Suddenly, hats and shtreimals are needed. Can anyone explain why?

(I asked someone about this last week. He said (with a shrug), "This is what you do," and added that one shul auctions the privilege of bringing the Rav's shtriemal to him. Last year, it brought in $15,000.)