These boxes are not easy to break... they're fiberglass not plastic... and if they're using anything other than what they have with them, it's premeditated and they could have a ladder with them and power
tools. Then what?
Oh, and unless you put a giant sticker on it that says "NVR INSIDE - DO NOT TAMPER WITH" most people won't even know what's inside of it, unless there's physically something that gives away what it is, such as a camera mounted on it.