it’d be fun to play vigilante and they screwed up. Now they’re likely facing life in prison if convicted.
= = =
This is a sobering thought.
Even without ‘fun’ and ‘play’, but a serious attempt to uphold the law is hard to do without screwing up.
And the legal and financial consequences are significant, even for a correct execution (NO pun).
Which is why it's sensible to leave things like that to the police.