Does anyone know of a way to copy-protect image CDs?
I've just come back from photographing a Swiss wrestling (Lutte) festival. I went privately, but when one of the organisers saw me at work he asked if I sold my photos. I said 'yes' and became the sort of official photographer on the spot.

He wants me to send them a CD of the images. I know you can watermark photos, but I'd like to protect my investment of time, knowledge and equipment, not to mention copyright, by making the whole CD copy-protected. This means that I can sell the CDs to individuals, secure (I hope) in the knowledge that they can't be copied and distributed within the wrestling club.
Can this be done? All advice gratefully received.