Showing cards on the river - oops

So, I was playing a game for cash (friendly stakes) and the following scenario occurred....

7 players. 3 played a hand to the river. Large pot to be had.
Player A checks
Player B goes all-in
Player C calls and also goes all-in (having a and b covered)
Player C mistakenly thinks player A has folded turns his cards and has A high straight. Highest possible hand.

But Player A still has a chance to call/fold.

no one round the table is disadvantaged by the show, but A is advantaged by avoiding the call and loosing the hand.

No collusion. C definitely wants to take maximum pot and knock out A and B.

Player A knows he's beaten calls for a redeal.

Consensus was to start the hand from scratch. redeal.

Fair??

Well that sucks you dont want to do that in the wrong game to many times, you get taking out back for a lesson in how to handle your cards.. lol

No redeal. Player A can fold, and C takes the pot. A benefits from the mistake, and C possibly misses out on busting out A. Deal next hand and move on.

No this is not fair. C-player made a mistake and showed his hand. (This in itself is not uncommon at some casino cash games. Players are allowed to expose their hand to get a read on others). Only thing you did was allow A-player to fold with losing more money. Your mistake = own it. Declaring a miss deal after the river is just stupid. Get a copy of basic rules. Or adopt some type of house rules to avoid this in the future.

typical river on pokerstars))