This is categorically untrue. They are not a secret due to the approvals required at a local level and by the FCC. Many carriers lease space on the same towers

This is categorically untrue. They are not a secret due to the approvals required at a local level and by the FCC. Many carriers lease space on the same towers, or have agreements to lease space from others in certain markets. You almost never get the site placement you want: you are operating in a built environment and have to work within those constraints. The problem is that knowing the co-ordinates of the tower does nothing to defend against Stingray-like devices: coordinates aren’t a means of authentication.