Thanks for the advice! I see how it would make sense if we had the money to go after people with lawyers. However, I can neither afford that nor am I particula

Thanks for the advice! I see how it would make sense if we had the money to go after people with lawyers. However, I can neither afford that nor am I particularly interested in having to do that. I mostly see it as a deterrent. Surely the same effect could be achieved by putting the purchaser's name / email address on there, without the hassle of steganography. The impact of seeing your data emblazoned on the PDF would probably be a bigger deterrent than a hidden watermark, though of course it could quite easily be removed by a determined pirate.