if someone bought some unpasteurized apple juice that happened to be near the end of its shelf life, then it was warmed to say low or mid 60s in preparation for yeast temps, then a slow-to-act yeast, it could be an issue. whereas similar practice with wort would not.
Not out of the realm of possibility and the cause of an estimated (link below) 16,000-48,000 case of illness a year
I poked around and found a thesis from 2003 on the topic here
. It does mention unpastuerized juices being implicated in widespread illness. On page 27, some info about contamination of cider (non-fermented kind) of raw product due to handling, processing and/or insects, animals, birds and rodents. The good news is it must not be all that common or Denny's reportable number of dumpers would be more than zero
Further down there is mention of methods which can produce a "5-log reduction" in pathogens (100,000 times fewer) which includes carbon dioxide and "high hydrostatic pressure" which I don't think 30psi in a keg would qualify (350 megapascals is over 50,000 PSI), but Co2 is certainly mentioned. Page 33 lists further ways to reduce contamination. I found it a really interesting read and I think some of you will too.
Things I'll do differently is make sure to purge O2 from my kegs after opening them (I don't typically do that with cider) and star-san the lid whenever removing it from the keg. Also, the day I racked the cider was later on in the afternoon after I had been doing some work removing a glass block window in the basement. There was a lot of "matter" stirred up that day and probably still some floating around. Waiting till the next day for things to settle would have been wiser.