If you plan to assign user numbers to users, you're going to need to provide an address to be used for emergency services (that is 911 in the US, 999 in UK, and so on). In most geographies, this will be required:
Managing emergency locations
Usually, you would specify the office address, but if you know that a user will be primarily (or frequently) working from home, it may be safer to provide their home address. You should consider the likelihood of calling the police or fire department from your Skype for Business client as opposed to your cell phone or a phone on your desk.
Be sure to schedule routine check-ups ...
