What you mention is not completely imposible, but unlikely.
We are not in a colocation, but in a office building. We are the only telcom people on the entire building.
The data circuits (wan) enter the building via T1 circuit to a ISP provider,on HDSL format.
The “demarcation” point and the routers are inside our space.
Not a easy target,considering that the office is manned most of the day and we constantly drop by at any time.
I found out that there are many small terminal servers that are priced bellow one hundred dollars.
They have a ethernet port and a serial port that could be connected to the console port.
The I.P. address of this device will be diferent than the gateway, and also the port could be changed to something diferent than the normal “23”.
That is what I will using from now on.