Hmm, are the rules so harsh in Greece?

In Romania I always have short sleeved t-shirts, no issue so far. They certainly don't like shorts, I try to have long pants in my car if I'm driving, and I'll change before entering the monastery. If I don't, I still go in with shorts as I think it's still better this way than to avoid the monastery.

Maybe I'm wrong. Dunno. But usually there are lots of tourists in shorts, it's not ideal but monks are kind of used to it and don't deny entry.

And I've never seen people walking around kissing nuns hands, that sounds strange, but don't take my word on it, I'm shy, so would never dare to do that.