In Denmark possession of CSAM was made illegal and it lead to police being forced to prosecute people who accidentally uncovered CSAM and wanted to report it. I haven’t heard of specific cases, but if you want to report existence of CSAM on a CD that is in your hands which you found in the attic of a home you just moved into the police will tell you to destroy it immediately and forget about it because the law can’t distinguish between the owner of the CSAM and the current temporary person that possesses it and reports it.

The fuuuuuck? Even in america, the stars would have to align for that to happen. The cop would have to dislike you, the prosecutor would have to dislike you (or be gunning for a higher political position and you’re an easy mark for being tough on child criminals), the jury would have to hate you (or be really dumb and not believe you took the material to the cops in the first place), AND you would have to be dumb enough to not realize how hated you are in your local area and still give them the rope to hang you with.