We used this rule to hilarious conclusions in one of our first 3E campaigns.
One of the characters, pursuing more selfish interests, had run off and joined a local thieve's guild.
The party, with the rogue absent, was then hired to protect a merchant wagon leaving the city, because of the dramatic increase in highway robberies.
This resulted in the party escorting the merchant wagon encountering a band of theives with their own rogue apparently a new member of the gang.
Combat began as the players attempted to fend off the thieves. The rogue began fighting with the party's lead fighter, and whispered to him "Play dead... we're going to take all the thieve's money". The fighter decided to trust him, and the rogue stabbed him, and the fighter "played dead". I had him make a Bluff check.
Then, I had EVERYONE, including the players, make a sense motive check. The other thieves mostly failed, and all the players passed... except for the mage. He was now convinced the rogue had slain their leader.
This led to the rogue getting blasted by a magic missle next round, as with wizard screamed "You traitor! You killed him!"