We had the same kind of "hidden" router at my previous employer, as we had a team of ~10 developers who needed a lot of different access to different servers and between eachother. We put the name of another tenant in the office building as the SSID :).

After about a year the network through that router started to slow down. When we checked why we realized that we had more than 40 wifi clients, as other (non-dev) teams learned about the network through the grapevine and actually the new employees from sales (the neighboring office) were told to connect to that network directly - as the process to connect to the "normal" network was too much of a hassle.