I'll open-complete when playing short-handed against weak opponent doorcards.
So, if I've got (7
4
)2
and my opponents have doorcards of Q
, T
, and 8
I'll open-complete.
In my game (30-60), the bring-in is $10. So, I'm raising another $20 to win the $30 in the pot already (four $5 antes and the $10 bring-in).
More importantly, I'll make the same open-complete with something like (4,9)2 against weak opponent doorcards.