They are more "secure" in that scanner manufactures don't license the technology to decode iDEN and some other more commercial type systems, probably because the market interest in monitoring these systems is limited. There might be some SDR community developments however...
I would argue that it is better for PD systems NOT to be "secure" WRT encryption, except for TTY, tactical and surveillance channels. The public / media have an important oversight function to perform over police agencies.
BGE and other utilities OTOH have a business case to keep their operations confidential to some extent - their PR reps would like to "control the message" as much as possible. Their perceived performance is important because they are a regulated public utility, and public perception plays into potential rate increases and other actions.