How would Texas Hold'em strategy change if it was possible to fold only in relation to a side pot?

Question

This is an open-ended question about how Texas Hold'em would be affected by a rule change.

Suppose we have the following scenario:

1. Short-stack A goes all-in.
2. There are two callers B and C.
3. On a later street, possibly after further bets into a side-pot, B folds.

In typical gameplay, B will win nothing, C will win the sidepot, and the strongest hand between A and C will win the main pot.

How would strategy change if B's fold relinquished his claim only to the side-pot, and he was still eligible to win the main pot, say because he has put as much money into the main pot as all other players?

I am interested both in how this would change strategies (for example, I think short stacks lose some power because their all-ins are more likely to be called by players who needn't fear getting blown off the hand in later streets) and in whether there are fundamental principles of poker that this rule change would violate.

Answer 1

It would make it pretty much always a mistake to not call a small all-in with any two cards. Like say a player is all-in for 1,000, and we have a stack of 10,000, and player C has 100,000 chips. Because we know we get to see all 5 cards for 1,000 to win 3,000 we can call way wider knowing we can just fold from the side pot if we miss and hope to hit runner runner. We will effectively get to realise our full equity with the 5 cards. A range of 50% vs a range of 30% from each other player is just shy of the correct odds, but knowing that you can always see all 5 cards at the minimum.

It would as you said take away all of the potential bite from smaller all-ins, and almost guaranteeing short stacks would be knocked out when all-in as pretty much everyone should be calling knowing they get to see 5 cards. Especially in situations where a player is all-in for like 5 BBs and the table average is like 30+BBs.

It would likely also give a lot more power to the big stacks. Knowing they can just take a side pot for free in most situations where they aren't just crushed by the other player who folds from the side.

Interesting thought but I think it would drastically change things. It would probably make it so you'd only see small all-ins in the niche case where someone was bad beat and left with less than 5BBs.