We have all benefitted from other skin developers' coding techniques. It could be a simple calculation or a full-blown technique for handling a major skin feature.
Sometimes this is offered in a forum thread, but sometimes a developer looks at another skin and says "Ah, so that is how it is done!"
Most of us freely offer our source code, and sometimes another skin developer replicates some of it in his own skin. There is nothing wrong with doing this, but I think that we need to ensure that we acknowledge the original skin developer's contribution.
It is polite that you should let the skin developer know that you used his technique. I have seen acknowledgement comments in a skin's source code, but the original developer may never read your source code.
Suggestion: If you acquire a technique from another skin, add a comment to the skin's page. E.g. "I replicated your technique for using Java anonymous inner classes in MySkin. It works well."
I don't want to make this too formal. I am suggesting that you provide some positive feedback. If we all do this, it will encourage us to continue with our endeavours.
BTW I am guilty of not acknowledging; I assume that we all are occasionally.