> “I know it when I see it” has been used in a court before.
It’s been used in a court, but not too much effect; the popular source of that is a discussion of “hardcore pornography” in a concurrence to a Supreme Court decision in an obscenity case which was notable for having a majority on the ruling in the case, but no consensus by any more than two justices on either a rationale for the ruling, or (among the dissenters) on the reasons for rejecting the ruling.
It’s been used in a court, but not too much effect; the popular source of that is a discussion of “hardcore pornography” in a concurrence to a Supreme Court decision in an obscenity case which was notable for having a majority on the ruling in the case, but no consensus by any more than two justices on either a rationale for the ruling, or (among the dissenters) on the reasons for rejecting the ruling.