I see your point, but most Chiefs of Police will be deterred by the knowledge they may actually get a fair-minded judge who’ll decide against them - and they’ll be very reluctant to deny an FID to anyone, simply to spend all that time and energy for nothing.
That right there is an oxymoron - when the issue is the right to keep and bear arms. The courts are generally hostile to the right to keep and bear arms. Chiefs of police have only a slim risk of being overturned.