Years ago I had an expensive road bike that a kid tried to steal. I was chasing him down the sidewalk as he slowly gained distance from me when a motorist who saw me giving chase, cut him off at the end of the block. I caught up to him and yanked him off the bike while a store owner across the street called the cops. I held him down till they arrived and put him in the squad car. I filed a report and never heard a thing about it.....
Lesson learned: beat the crap out of him the next time and let him crawl home on his own since the cops won't do anything.
So yes, I approve what this couple were doing........