Question on Showdown Rules

[brer]

I'm looking at Robert's Rules of poker and I don't understand what this means:

5. Any player who has been dealt in may request to see any hand that has been called, even if the opponent's hand or the winning hand has been mucked. However, this is a privilege that may be revoked if abused. If a player other than the pot winner asks to see a hand that has been folded, that hand is dead. If the winning player asks to see a losing player’s hand, both hands are live, and the best hand wins.

Can someone elaborate? Perhaps with an example?

[asdf1234]

You bet your pocket aces on the end and are called. Your opponent looks at your hand and begins to throw it in. Technically, you, or anyone at the table has the right to ask that his hand be turned over as well. If you are the one to ask and the hand is turned over and it happens to be better than yours, then you lose the pot and look like a giant ass. If another player does, the hand is declared dead first, then turned over.

Generally it is bad etiquette to invoke this rule and some players will get very upset.

[Piiop]

Let's say that at the river there's a showdown between 3 players A, B, and C. A shows his hand, B shows his hand which is better than A's, and C mucks his hand.

Any player may request to see player C's hand. Any player could request this to get information on player C, to see what what he was played/how he was playing. This is sometimes considered bad etiquette because the player has already lost the pot. Forcing the player to show might make the player more embarrassed or frustrated. If someone has been losing a lot and playing poorly, you want them to stay at the table, you don't want to force them to leave. If any player but the winner requests to see the hand, the hand remains dead.

However, if player B (the winner) asks to see player C's hand and it turns out than player C misread the board and actually has the winning hand, then player C's hand is live and he is awarded the pot.