FAA Guidelines are always followed.
You say that "drones are noisy". I agree that a UAV like the Phantom does produce a bit of noise but at the average altitude of 100 to 150 or 200 feet AGL you would be surprised how little attention it attracts. Most people don't even realize that is is flying overhead as it tends to blend into traffic noise and other background noise common in the city. That said, the noise is a benefit as the UAV, when heard, lets people know that it is there, that they are potentially being watched and it serves as a deterrence to negative behavior. This is similar to why we often conduct our mobile patrols with the light bar on the roof flashing.
You mentioned the wide field of vision. Yep. That is a good thing in that we can observe more but I have been vocal on many sites lamenting the fact that DJI seems unwilling to look past cinematography cameras and give us like a FLIR thermal camera and a short range digital zoom on the Phantom model. While the camera image is great, we really desire the ability to be able to stay up at ~150' yet zoom in (say 3 or 5 x magnification) to see what a subject is carrying. Situations like when we make contact with vagrants on our properties are dangerous and it would be beneficial to be able see what is in their hands before our officers approach.
The UAV is great for patrols and a good way to observe and document but with a short range zoom and maybe an option to switch to Thermal without having to bump up to a larger, heavier platform such as in Inspire or Matrice it would be even better.
We have recently used this video to point out some of those pros and cons,