Well, excuse my ignorance but I'd be glad for some explanations. "It is clean daft so you just don't do it" would have done in the bad old days of usenet; on the internet forums of the 21st century some explanation may be demanded.
For myself, I do see the restrictions that
-) as already said, thermoshock is a danger to be avoided, and transparencies are particularly prone to it so care would be needed;
-) an abundance of water might well leave remains in hidden hooks, that might refreeze, increasing weight, possibly beyond margins. So one would want to apply water sparingly - another reason to have it as warm as practical - and dry it off after application.
Agree on these two?
More arguments?
I'll admit I've never been in the situation, always having been able to rely on people more competent than myself, mostly instructors. Also, up till now I've only flown well-hangared club planes. So I'll be glad to learn, just wondering.