It is not the CB,s problem. It is just allowing a "load" as any other such, as a 1500 watt heater, transformer, ballast, whatever.
The "hum" or noise is the same as with mentioned loads,
The service upgrade would just make the BX hum all the more.
BX clad is an impeadance/load and not an EGC.
So the breaker doesnt care. Until overload occurs. No that is subjective depending on many variables
