“family member who is LEO”
I agree with the stated use, however, the system is set up for abuse.
It’s the police keeping track of tickets or toll violations. The unknown tags could still be reported to the issuing authority for correction.
The issuing authority would know who the plates were given to, so the same issuing authority can make the violator pay the fine/toll.
As far as public inspection goes, you could have actual identifying information removed, i.e., at least the public could see how many such tags were being abused, even if they don’t know who the individual is.
Of course, I’m sure the gov could still shield itself from fines if it wanted to.
To me, the “answer”, is not to get rid of secret tags, but to get rid of automated enforcement.
If he does something stupid, he probably gets in more trouble than just a ticket anyway, because if the infraction is of note, it IS reported through the brass to his commander...