I know to my cost that this is not all that uncommon.
This is what has happened to me (three times so far)
Photographer takes a snap and puts it into a photo library.
Company Ad agency sees snap and says 'we like that and are going to use it'.
Ad agency pays library and they use the snap.
Ad Agency neglects to pay Photorgrapher
Snapper sees ad beingused and wonders why they have not been paid for it's use
In my case, I issued a DMCA Takedown notice for breach of copyright. This got the Company's attention. I got a very nice letter from their lawyers explaining that they had indeed paid a licence for said images. They included the details of the payments made to the Photo Library.
I removed all my images from the Library and sued them for triple damages just like the RIAA do to unfrtunate downloaders. Remember here that they had been paid for the images but hadn't paid even $0.01 to me.
They ignored my suit until I won and sent in the bailifs.
The snapper here should probably have sued the library but hey it's Apple (or rather their Ad Agency) who has used it so lets sue Apple and get some free publicity.