No never heard of such a system. Is work that can be backed up more important than life safety......NO.
I have many computer suites in my charge, none of them have this, and the occupants are expected to leave immediately as normal practice.
I also have an internet suite protected by a roller shutter, when the AFD operates the shutter descends but the occupants of the room are introduced to wall mounted signs that tell them to evacute immediately on hearing the FA and seeing the beacon flash in the room, in case they are wearing headphones. Which some of them do whilst using the computers.
In the system you describe I would be concerned that even with the screen message USB keys (memory sticks) would still not be left by the individual and there will be those that stay to ensure they retain ownership of the data.
This seems a bad practice, that kind of goes against "do not stop to collect personal belongings" etc etc etc..... and all other such good messages.
I would certainly review the management principles in the premises and any training requirements that both may need adusting/reviewing/freshing of the current policy.