I'm sure it is quite nice to have, yeah. Any unfair advantage you can get tends to be nice to have. That's not really the debate, though. The issue is that while it's nice for you to have, it's also a lazy band-aid of a "solution" that feels unfair to everybody else and doesn't even try to address the actual problems with current gameplay.
Yikes, you're an art student, right? Makes sense. Well, the PD party, not only a pretty awful job now, but it is filled with new players. New players go onto servers, and PD jobs allow for them to learn and gain a stable income. Getting random people to coordinate is funny. You are thinking of it like a regular base party where they all most likely know each other. So yes, a little handicap notification would be nice.
So the police find it difficult to defend the PD whilst completely ignoring it and staying as far away from it as possible? I'm pretty sure that's just things working as intended. Coming up with an effective way to keep the PD secure should be a core part of police gameplay. They have to put in effort and overcome challenges to accomplish their goals. They can't just ignore one of their main objectives and expect the game to play itself for them.
Why should the raiders be responsible for notifying you of their raid? There's nothing wrong with the police having to think a little and communicate amongst themselves if they want to be effective. With a single message in team/party chat from an officer stationed at the PD, you've accomplished the exact same thing with the added bonus of it still making sense in character.