Mine have been responsive. My YWG was picking up sand all around them and dumping it on them the other day, they closed up of course. Then when I was moving a rock, and set it over them, they closed up as well.
I think we got pretty lucky with no melt's at all, everything I have read, it is usually used to ship colony's across the world and they have 5 polyps die, but out of a colony of 100, thats nothing. Here in the US though, we have those nice little flat rate shipping boxes, so its easier and safer and the same cost to just ship them in water. But shipping over sea's is different.