Very interesting topic. I, like Noahcat, am also blessed/cursed with the ability to see every hand 3 machines in either direction. Most of my friends don't notice other peoples hands, and tease me like crazy for noticing. I play alot of VP and generally know what to hold as the 5th card is dealt. My LV buddy jokes around about my comment to "Hold the 3's!" as he was holding a king, not noticing a pair of 3's in his hand. One of my local friends holds, then unholds, the card as she is making the decision. I absolutely cannot sit by her, even tho she usually ends up deciding on the right play.
That said, I've moved a number of times when someone beside me continues to make stupid plays, it distracts me to no end.
As for offering advice, I don't say anything unless asked. To your example on the Aces/ten full house, I've had a neighbor ask what I would do...I answered, hold the aces. They said "But I never get the fourth ace". My answer is - they are playing DDB poker, if they want to hold a full house dealt with 3 aces, they should be playing JOB. BUT, if you're gonna play DDB, the correct play is hold the aces.
By the way, she held the aces and got the 4th (no kicker) and screamed "You were right". I replied "The play was right, even if you didn't land the 4th ace. "
It amazes me the number of people who obviously don't have a clue about VP playing the machines.... very painful.