Would they really be happy with 100 photos from a wedding?
I wouldn't. We got way more than that, and the photogs were shooting Mamiya 645s (the film ones...and I've got the stack of negatives to prove it...).
Back in the film days I shot maybe a dozen weddings a year...mostly for corporate clients. Shot on EOS 1n bodies, they always seemed to average around 15 rolls of 36 exposure neg film. That equals 540 mostly thoughtfully composed shots. 20 rolls was HUGE. A massive 720 frames! OMG.. And it was tough to edit.
My weddings PA has probably dropped to more like five or six a year, still mostly for corporate clients, and the thought of being restricted to 540 shots scares me. These days weddings seem to run to around 3000. After a brutal edit, the client gets around 250 shots. Comparing the wedding images now with ten years ago, the freedom to shoot completely unrestricted is delivering brides great shots that leave the old 15 roll wedding deliveries gasping for respectability.
So in the context of this thread, full time wedding shooters would hit the shutter life cycle sooner than most. But a 100 photo wedding? Maybe this was the number of images delivered to the couple rather than the number of frames the photographer shot on the day.