Poker etiquette--showing mucked cards

I know on JS if you are dealt into the hand, if the hand goes to showdown you can look at the hand history and see the mucked hands without having to ask. I dont think they show on ACR so i guess the rules are different because it is a players "right" to see mucked cards if they were dealt into the hand. If i am just observing, the mucked hands dont show up in the hand history viewer. As far as etiquette, if i can gain information on a player based upon position and how they played a hand I would do it to help learn more about the player especially if i have never played against them before regardless of any criticism if its my right as a player at the table.