Kind of, but the lower you get, the less discrete it is. Plus, the technology aboard, at least currently, is lightyears behind what you'd be able to get with a full kit on a helicopter due to the weight limitations.

Also, considering how much those helicopters can zoom, they can be pretty far off, laterally, from where you are and still get a lock on you. Drones have to be more or less above or else they're going to be getting a hell of a lot of resolution. The technology the police I took photos of had in their drone didn't zoom, and this is what I looked like across the room from them.

Of course, technology will change and quadcopters will get better at what they do, but as it is now, it still doesn't really reach a helicopter in utility.

Honestly, just like any other tech, we have to trust that the checks and bounds in place are effectively force a cop to use a tool at their disposal properly. Of course there are bad cops and bad departments, but I don't think a drone is much more stealthy than a helicopter.