Honestly, my dog eats hairs all the time, he's never had a problem.
Well except, and sorry to be graphic, but sometimes when he poops, it is left dangling there by a hair he's swallowed.
At which point he comes to me and patiently waits for me to get a paper towel and remove it.
In all the years I've had him, that's the only issue with hair eating that he has.
ETA:I've avoided this thread all day, simply because of what I thought
the title said