siteguru - My original post stated may or may not know.... this indicates that not every one of my customers knows anything. I am not worried about "normal" customers... I'm worried about the php-savvy people who think they can simply steal someone's application and sell it as their own.
Gybbyl - Yes, I happen to be a php programmer, and I do write massive amounts of php. I also happen to sell 5 different applications I've written over the years. With sales of approx. 10-20 licenses per day, I am rightly concerned about theft of my work. (And therefore my living!)
If you made clay pots for a living, and someone was stealing a few out of your workshop every day, or worse, stealing your customized designs... and then selling them as their own.... wouldn't you also try to figure out how best to "protect" your work?
The way I understand it... if there ARE ways to protect yourself, then why not take advantage of them. Yes, I believe in helping others, and open-source, and whatever.... but I am trying to make my living from selling my software, and I don't appreciate people stealing from my CHILDREN!