I can imagine the headline now:
"Sleeping Toddler stolen from Front Garden, whilst Mother and siblings played inside"
And believe me, you would be Public Enemy Number 1. Mothers up and down the Country would be slating you for neglect.
Because, what sounds Ok in theory, can spin on a dime, in the wrong set of circumstances. Imagine. One of your DC that's inside, traps her finger in a door/squirts paint in her eye (insert a thousand possible distractions). A person who knows your usual routine, could have that child snatched in under a minute.
The question is: Is it worth the risk?
For me? No. Wheel the buggy in to the hall, unzip the footmuff, lock the door.
Need we remind ourselves about Madeline?
Whilst not to get in to a debate, about the rights and wrongs in that case, let me remind you, that in the 70's, everybody left their babies and toddlers in their rooms at Butlins. Everyone. And a staff member would patrol the camp, and write on the board what rooms they could hear crying from. You wouldn't do it now.
Ok, I got a bit off track, but hopefully yswim.