Clone scripts from sites such as ... are perfectly legal to use. Since the original scripts from which these have been cloned are server side scripts where the author of the clone has no access to the original source there can be no copyright issues.
I'm not sure I understand that. Are you saying that the author of the clone copies the functionality of the original, but not the actual source code? In other words, he creates an entirely new script, but one that does the same thing as the original?
If that's the case, then of course you are right - it is not illegal. The clone author is merely copying the idea, and, as we know, there is no copyright on ideas. I understood from the original question that it was the script itself - the actual code - that was being copied. That would be an entirely different matter.