This whole incident is an object lesson in avoiding adverse situations.
The facts are: Four young men were in a car. Together. At 2AM or so. In a closed park. Withat least two guns in said car. And a small amount of marijuana.
Out of all of that, only the marijuana is illegal. And even that is only marginally so. On top of which, there's no reasonable way to determine who it belonged to.
But unless you have a Pollyanna outlook on all aspects of the world, you have to admit that the combination of all those undisputed facts is a bad look.
It would appear that the cop was selective in his arrests. And that the case was essentially un-prosecutable.
But if they don't put themselves in such a vulnerable situation, none of this happens at all.
At an entirely different level of severity, there are parallels between that and Kate Upton strolling by a construction site in a thong bikini and stiletto heels, then complaining about sexual harassment when the inevitable hoots, hollers, catcalls and invitations pour forth.
She did not one thing illegal. But she put herself in a situation where the results of her perfectly legal actions were reasonably predictable, and everyone all around would have been better off if she'd used just a smidgen of common sense and discretion.
Legal actions aren't always smart ones.