Prosecutor laughing

My thought is that perhaps they're happy people.

Seriously, whether or not some sort of contempt of court should be levied I'm guessing is your or your friend's concern? What is the context? What are the circumstances? Sounds like possible paranoia.

outside of the court context, there's a decent chance the attorney and prosecutor are friends. they're colleagues, they may have gone to school together, they may have worked together in the past. it's not at all unusual to see opposing counsel enjoying each other's company when they're not arguing a point

I attend many mediations and arbitrations as a course of my employment. When it's coffee or lunchbreak time, opposing counsel often hangs out together.

They're more likely to be friends than enemies - or even neutral.