[Niediam]

Folding the river because of villian's AF is bad because our sample size is way too small. AF converges relatively fast but after 50 hands I wouldn't be surprised if this guys AF was really 0.25 or 2.

I'm certainly not suggesting that we disregard AF's completely when their accuracy is in doubt. Using it to help decide what to do in a very close decision is perfectly fine. But folding the river when you make toppair/goodkicker for one bet in a 8bb pot when the river was a scare card isn't even close to being close.

As to those who want to c/c the river I think overall its higher EV to bet. Let thinks about some of villian's possible hands:

If he has a 7 he is almost always calling a river bet but will often not bet himself.

If he has a 6 (straight or flush draw on flop) he is almost always calling a river bet but will rarely bet himself.

If he has a a pocket pair 88+ he is always always calling a river bet but may or may not bet himself.

The only hand that we beat that we would really want to check to is missed overcards. He may or may not bluff these but in general I would not expect a bluff.

Obviously if villian has a flush we don't want to put two bets in but really there isn't any reason to believe that he has one until he raises the river.

It's unlikely that villian has a bigger ace (even though A7 and A6 are certainly possible) because he only called preflop.