I wouldn't leave my children (6, 5, nearly 4) in the house alone at any time, largely because I'd be more concerned about what would happen if something happened to me.
A couple of years ago two of my children were at nursery and one was with me and I slipped in the street and ended up in hospital with a head injury. Fortunately, I was with my friend, but had I not been, no one would have known to collect my children from nursery, let alone if they were home alone.
So no, I'd never go out somewhere and leave them.
But then on a summer's evening, DH & I will sit in the garden while they're sleeping.
MillyMollyMoo, how far from your house is your bin? I'm not saying you're wrong, btw, it's just that I wouldn't think twice about putting the bin out or tipping the water from the mop bucket down the outside drain, and my children are a lot younger than yours.