My Cards are ordered, with a space on back to handwrite.... I'll attach a couple pics...
On my Website, I have to have pics in a "Gallery"...So clients have to have a 'Gallery ID' & Password to get in. Also, Most of the pics are hidden from visitor view, so they have to search (a link I call "Your Fotos") just to locate them.
I do a lot of Photoshop Composites, editing/repair, & (comes in waves)... editing of other photographers pics (Portrait/Commercial/Wedding).
So they don't want anyone to see their pics on my Website.
& my Cards have to be somewhat 'generic' in nature, because I might be at an event, and have to hand one out for a Photoshop project, then turn around and hand another out to someone wanting copies of wedding pics, because they live out of state.

It's a work in progress.. And I think I'll steal some of the other ideas you have been recommended :)

Again, I don't work FOR shootproof, but use them. A nice feature is that nobody can look at any gallery that I don't want to see it. The link takes them ONLY to the gallery I want them to see.

I have enough time to prepare for the marathon this year. To save the aggravation of cutting out a few thousand strips, I may go ahead and get cards like yours, and put the QR code on the back. Of course, anything left over will be wasted money, but saving time cutting them on a paper cutter is probably worth that to me.