Don't take for granted the other Crestron Dealers in the area feeling the exact same way that you do. Everyone hates this kind of thing. Give them a call, get together and come to a gentlemens agreement that nobody will touch this kind of work in your area.
If the guy is buying online, he's certainly too cheap to fly somebody in from 1/2 way across the country to install and program. You've effectively "locked" him out of the area. Now he has to buy from one of the Crestron Dealers in the area, and may the best salesman win.
I know it sounds a little crazy, but I did this very thing a few years ago. It has worked out great for me as well as the other CI's in the area because we've built relationships and help each other out from time to time. It works out nicely. Just because we compete against each other doesn't mean that we can't be on the same team when it comes to protecting out livelihood.
