As long as electricians have families to support, side work will happen. I'm not saying it's right, just that it happens. It's just like DIY, it's not going away either.
Every time work slows down I always see the guys with the union t-shirts in Home Depot buying....gasp...electrical stuff.
Uninsured, after all is said, this is the one that can destroy not only frendship but if anything goes wrong it can destroy the rest of your life. Stay frends, and protect yourself.