I would suggest to simply create polkitd user and group using useradd instead of systemd, ignore the error message indicating the user exists or whatever might happen, and then try to use the polkitd user. If this last step fails, then the postinst script can exit with an error.
I don't know of any other package (except for systemd) using systemd-sysusers in its maintainer scripts, but I've got 33 packages using useradd or adduser just on my Linux desktop. IMHO this approach would be reasonable. Closing the ticket is fine with me. Regards Harri
