most fender amps these days are not on turret boards and are on PC boards using Nylon Jacks that are not tied to Chassis ground as the old PTP wired units indicating some sort of solid state , tube combo ( All SS amps do not tie to Chassis ground, and all the jacks are nylon ) not like the older switchcraft jacks that were used in the turret board units.
I suspect that the modern assembally plants in China would have to tie the ground to the chassis and this may cause some interference and become a noise factor, due to the modified design of the amps ,
I just did a recap on a 65 twin BF RI, it resembled more of a tube powered solid state than the Twins predecesor and on top of the sloppy cold soldered connections that broke blowing out all of the filter caps there was multipin connectors that were not soldered correctly and the unit was riddled with cheap components .
My point is the redesign of the new amps is not the same as the vintage units although the circuits may be similar on paper, which may be why the out let is not included ,
It may be easier to remove it by design than to properly install and shield it, JMHO