derSchwartz said:

If I understand correctly, the main reason generally not to do this is because once antes kick in, the initial pot plus our open raise plus a re-shove to cover the rest of our stack at 20BB should provide us good pot odds to call. If we have 19BB, blinds are .5BB/1BB/.1BB and we are 9 handed, the initial pot is 2.4BB. If we minraise from MP, it's 4.4BB. If the BB started with 19BB and re-shoves it's a 22.4BB pot. We have to call 17BB. Provided that we are opening an appropriate range, our equity should be good enough against an appropriate re-shove range given the pot odds to call.
Is this a decent basic explanation?

A few other reasons I could imagine for this rule are:
-because otherwise our open raises look weak, like we might fold them more often than we actually would
-because otherwise we look like scared money
-because otherwise we are left with that much less than 20BB

Can the following be reasons to break the rule – to open raise and fold to a re-raise with under 20BB? Suppose you have 18-20BB and:
-It is the final table or near it and nobody has more than 20BB
-We have an excellent read on a villain
-With tight players in the SB and BB, we decide to open stab with a weak holding, and somehow our EV is negative against those villains if they re-shove?

Thanks for your thoughts. Have a good evening.

Hi DS. Your initial summary of why you wouldn't often raise-fold such a stack is a good one. The “few other reasons” you list are, to be blunt, crap. If your opponents start jamming too wide against your open raises, that's a good thing for you, because although you might fold your weakest hands more than you'd like, you'll win more with the rest of your range. The other two points, about “scared money” and being left with less than 20BB, don't seem to me to be connected to EV in any way.

Did you ever pick up the premium podcasts? Nate and I talk a bit about this. But yes, there's no rule that you have to call a shove if it's -EV to do so. So if you are confident that you don't have a +EV call against V's shoving range, either because of straight cEV or because of ICM, then you should fold. You should be aware, though, that if ICM is going to force you to fold an otherwise profitable call, it may be a bad idea to open in the first place, because smart opponents can jam really wide on you to take advantage of that.

This is something I do most often in EP. It may be that I have a hand good enough to get in against a jam from the blinds or a late position player, but if I open AJo UTG1 and UTG2 shoves for 18BBs, I probably want to fold.

If you are literally never folding after open raising, then you probably shouldn't be open raising at all and rather just shove.