No way would I leave my door open all night. And I'm in the city -- you'll be surprised at the action that's going to be attracted to your backyard once you add a chicken-dinner-at-the-waiting...
Well, your husband is right - they will put themselves to bed at night. But unless your run is bomb-proof, and I mean REALLY reliable, then you will need to go out and close/lock up their door. Besides, they're sleeping at night. Going out in the morning to open a pop door will take, oh, 30 seconds - not a big price to pay for piece of mind.
Believe me, there are plenty of folks here on the BYC that don't lock up the chickens at night, but there are also lots of people on the pred forum saying they never thought an attack would happen to them either...