[ruined]

one person walking away from a police encounter doesn't mean police think that person did not break the law.

prosecutors may take their time and file charges at their leisure.

[JohnFen]

That may be true in the abstract (although it doesn't matter if the cops think you're breaking the law. What matters is whether or not a judge does).

However, neither Border patrol nor ICE have been exhibiting thoughtfulness or patience, so I doubt they're playing any such long game.