This doesn't seem like a prudent thing to do. If 1/2 of the airport is
obscured, how would you know that the rest wouldn't fog up in less time
than
it took to land? IMHO, it would be best to fly the published approach and
be
ready to go missed.

I tend to agree, although there may be a situation where you're vectored
directly overhead the airport but the procedure may take you several miles
out and back...just in time for the airport to fog over completely.