No one wants to be the weak link that gets their name blasted in newspapers when a kid gets harmed. Not that it would really be their fault, but the incentives are obvious to "play it safe".
I feel like "playing it safe" could have been accomplished with the officers just dropping the kid back off back home. I don't see why it would escalate to pressing charges.
2 months later when something happens to the kid this entire thing will get replayed in the media and everyone that didn't do anything will be made out to be a villain.