I guess I don't really understand why you wouldn't want them to know what the source code looks like. I mean, they're the users. If you don't want them doing things that are in your opinion "bad", you chose the wrong language. Remember that perl is all about providing options and serving others. When we start writing code that gives users fewer options, that doesn't serve them any, and "what good is it then?"

By the way, I don't think you could write a program that flawlessly obfuscates any piece of perl code using variable substitution because that could caus major soft referencing problems. Solving that problem is (probably) reducable to Turing's Halting problem, which is best left alone.

-Ted