Just that really? Going to be at home with the kids a lot over school hols. Could I nip out for quick run/shops for 30 mins with the 13 year old in charge of the nearly 7 year old. With strict instructions not to open door, cook, go outside etc. I never have so far but think I can be over protective at times so I find it hard to judge.
So:
YABU - yes 30 mins is fine
YANBU - no - that would be completely negligent!