Laughing at, not laughing with 21

We are going through a learning curve here in the mad house. I try to let my boys have freedom, I believe in letting them play outside and try to encourage them to be independent, but with two boys who are 15 months apart there is a fine line to walk. Mini wants to be out with Maxi and I want to encourage them to look out for each other. In order to help facilities this we have purchased a set of walkie talkies for the boys, which work really well when they remember to take them out! But yesterday things went wrong.