I've only had permission asked from me once. I'm not going to get all high and corporate on my fellow community, that's just acting like the companies I hate the most, I'm sure you can think of those copyright nazi companies I'm thinking of...
I shouldn't and won't ask for permission to view someone's code and make any personal modifications or fixes to it, I will and do respect when mass amounts of graphics are re-used though so if I was going to release a new skin based mainly on another one I would ask permission to use the current graphics etc out of courtesy.
So yeah just to recap, as long as thanks, and respect where thanks and respect are due I'm happy. Which is the main reason I write the tutorials too, so I can help others, if someone cloned them off me and claimed as their own I'd be pissed off. But so far people have asked to translate it and host it on separate sites so I have no problem with that and of course gave them permission straight away