Just out of curiosity, I just checked.
Good news first: the phone software has no problem at all with removed modules.
The camera app just switch to the front camera when it does not find the main camera.
And when both camera’s are removed, the app just closes with a warning.
However, since the front camera module also holds the earphones plug and ear speaker, you can only make a call in handsfree mode (the main speaker is appearantly in another module.
Oh, and the empty hole where the main camera is located isn’t very pretty…
So if you don’t mind to loose the earphone connector and calling in handsfree mode only, you can use the phone in your company.
BTW, please don’t take this as an invitation to suggest more experiments on my phone 