Had a nasty spot in Gala today, wondering on peoples thoughts ethics-wise about this. Last Hand of the night, 630am. A chap who everyone calls Rastafish, shoves £50ish on a flop of

. Sean zerofive Belton reshoves, everyone else folds. The board runs out

. Rastafish tables his hand -

Sean says "thats so sick", Rasta says "was you in front?" Sean says "I was infront till the river"...there's a couple of comment speculating what Sean had, as the pot is being stacked up to pass to rasta. Sean's hand is facedown over the line now, but not mucked or even close to the muck. The speculation about Seans hand now prompts Sean to show his hand -

I didn't even think about it, instinctively said "that wins Sean". The other dealer and other players also noticed this, though I was the first to say anything. Sean apologises profusely to Rasta for the mistake/slowroll and was awarded the pot, but Rastafish was extremely angry at me for alerting Sean to the fact that he had won.
I immediately apologised and thought I was at fault. But do players have an obligation to point this kind of thing out?