How about packaging the script into an executable with pp?
I'm not sure how hard it is to pick an executable apart, but I guess it would stop all but the most savvy people from having a look inside. Of course it might interfere with the functionality you want from the script... nothing is perfect, I guess.
Hmm, easier then I thought. Still, if the user has no idea where the .exe came from, they might not think to try and unzip it. It's certainly some level of protection. I guess it all depends on what the OP wants to do.
The Security through obscurity debate aside, it is a barrier I agree, just not a particularly tough one to overcome. Add to the mix that by default pp doesn't clean up after itself, that is to say that once the executable is run the entire contents us extracted to a temporary area, so that it starts up quicker in future. This would be trivial to find when all modern operating systems allow users to find new files created (within a date or date range).