It's called "self-insured" and "risk-management" and a lot of luck so far.
Pinnacle is self-insured up to (I believe) $1 Million, meaning that if they bend an airplane up to that amount, insurance doesn't pay a thing, comes directly out of the pockets on Noncaring.
Second, Risk Management. Senior management discussed this once in a pilot meeting when Pinnacle first started getting the 400 hour wunderkids and the Captains were p*ssed about having to take up the slack with what these guys didn't know.
Indeed, my thought (which I voiced to management) was: if I have to do O.E., I want to get paid Check Airman override.
Management said that it's all about the numbers and how much risk you're willing to take on. The odds of anything going wrong are fairly low. The odds that it will be something the Captain can't handle as long as you can stabilize the airplane and let the low-time guy fly the automation while you, the Captain, handle the emergency then you, the Captain, perform the landing, are very low as well.
They're willing to accept that risk, and with the only 2 major accidents in the jet being guys that had high total time (even though they had relatively low jet experience), there isn't enough data to pin it on (even though the 3701 accident F/O was low time as well. Don't remember the MKE crew times).
They've used that data to talk the insurance into accepting those mins, although I'm sure they pay a higher premium for it.
That's one of the main reasons Terry Mefford was so inflexible about Captain upgrade minimums. Low time in one seat is a recipe for disaster. Low time in both seats is like baking the cake and icing it yourself.