If it's raining enough for me to think about worrying about my mics getting soaked, odds are I've already blown off the show, as I have no desire to stand in the rain, one shower a day is my limit. that being said, I have had plenty of shows in rain without the mics getting wet. key is windscreens or other foam on the capsule, even in torrential downpours, it's unlikely the water will seep all the way through both the hat and the foam. Of course be cautious and also tape around all connections (capsule to active/remote cable, cable to body, body to xlr).
I have never had a problem using the above precautions, never seen even a drop of water on my mics. I havent really done any rain taping since the GD days though, as unless it's a legendary dinosaur rocker that I may not get the chance to see again, I'd rather stroke it at home than stand in the rain.
I HAVE heard the results of Schoeps MK4V's (luckily not mine) under protected in the rain and yeah, that can't be good in the long term, though they did dry out and work fine now.