If you were to be walking down the street and for no particular reason walk into a probability lab and watch two scientists immediately flip 76 heads in a row t

If you were to be walking down the street and for no particular reason walk into a probability lab and watch two scientists immediately flip 76 heads in a row then, based on observed evidence, you'd be inclined to believe an unfair coin. But that's very unlikely to happen if you've got a fair coin. Almost certainly you'll flip ungodly zillions of failing sequences first before hitting any particular pre-ordained target. So with a fair coin the story is that you peep in on a probability lab and then wait there until just before the heat death of the universe and suddenly observe 76 heads. So honestly, in any fair coin situation your Bayesian probabilistic update going on will actually be predicated on very different evidence.