[_D&L_]

Reading pulsating veins has to be considered "part of the game," largely because its an unvoidable aspect of playing the game. All players will exude body tells, that are to a more or lesser degree, readable by other players, whose skill at reading the tells will also vary.

The only arugable difference with the shakey hands guy is that you saw his cards. There was no skill involved in reading his tell (u saw the cards), and no chance that he was trying to trick you with a false tell (e.g. false excitement, using knowledge of his own tell to his advantage).

So that's the difference. Whether its "wrong" to use knowledge of seeing another player's cards who has shakey hands depends on what you think the game of poker is about. If its about rewarding the most deceptive, cunning player at the table, then its ok to use the info. If there is an implied skill requirement in reading another player's hand, then it wouldn't be ok - because it involved no skill in reading his hand (but arguably a lack of skill on his part)

In my opinion, it would be ok to use info in either case.