My experience with self-defense:
Years ago I returned from Triglav too early. Noticed damaged vehicles, noticed the crooks. Called the police directly. Crooks were caught.
Continuation of the story; as main witness had to drive the car to the police - seizure of traces, report, forms, identification of perpetrators etc. 2x at court hearings. Of that, first time wife, owner of the vehicle, 1x myself. Some hearings were postponed. Threats from the court with forced escort if we don't attend the hearing. Summons to the wife was written so that we didn't even know what it was about.
At the last hearing perpetrators weren't there again, of course no forced escort for them.
Conclusion was that we witnesses were instructed that the court can call us again.
No epilogue, perpetrators who damaged over 20 vehicles got away without punishment.
I learned something from this story

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And addition: Police handled it very effectively and professionally.