One situation is when it puts the person you are putting at a
disadvantage by doing it (the guy on your right) on megatilt. I remember
I kept doing that to a guy at an Indian casino in Oregon and he
practically had smoke coming out his ears. He blew through a few buyins
and then stormed off. It's a dick move on my part, but poker is poker.
Whatever works.
There really are times when you KNOW with virtual certainty that you
have no shot to win a pot with your cards, that you aren't willing to
bluff on that hand, and/or that a bet is coming if you check. So maybe
by "checking out" in some situations you are cultivating a certain table
image that you believe is favorable for those game conditions, while
giving away only a miniscule amount of EV. Let's face it, to most
average players if you "check out" you look like a real rookie.