I think that is a great idea and pretty simple to implement. Lat year was my first full year in business and when I looked at the numbers, a large part of my business came from referrals and repeat customers. I think a simple referral plan as Brian mentioned could boost sales even more. Maybe a free bottle of spotter or credit towards future cleaning for the referee, and some form of a discount for the referral?
There are several things we could do with this and it would be very simple since we pretty much leave cards behind anyway as Brian mentioned.
Danbo 8)