Spoletta: it looks to me as if the kids are just doing a demonstration.
It looks that way to me too. Maybe something as simple as a demonstration on how to witness to someone who calls you, like a relative - an example of "giving a thorough witness at every opportunity."
(That is something that, notably, Governing Body members refuse to do, ala Gerritt Losch, who refused to appear in court to testify regarding Watchtower's child protection policies, using the lame excuse that "I don't answer to Watchtower." That would have been a perfect opportunity for the GB to practice what it preaches to JWs, but instead Gerritt Losch passed on the chance to "give a fine witness.")