[Mike Haven]

It is silly not to look at your cards before you bet, so there will be few occasions where you will bet a random hand, (any two cards).

The worst hand is 72o. Against a random hand, all in, it needs pot odds of 1.9 to 1 to break even in the long run.

The only time you should even think of calling with a 72o is if the only other player has gone all in pre-flop in the dark and the pot is offering more than 1.9 to 1, or if your call all in of a bet he has made in the dark gives you more than 1.9 to 1 pot odds.

Obviously, these in the dark situations don't occur too often.

Once he has looked at his hand, you can no longer consider his a random hand. He might only go all in if he has at least one card over an 8, or whatever, and your call should take your estimation of his betting standards into consideration. Again, it would be a rare situation, (but, admittedly, possible), where you would conclude that he would bet literally any two cards.