Clarification: I am not talking about shielded connectors here. This is only for connectors that have smd or tht pads purely for mechanical strength. These “pins” do not offer any electrical connection to the cable. Examples would be the two metal pins encased in plastic on the side of Molex picoblade connectors
Why would it make sense?
In some cases it might be a good idea to connect such pads to a larger copper area (=zone) to increase the mechanical strength or to allow that zone to connect to an area that would otherwise be blocked off by the mounting pads.
What would be the cost?
We would need to add special symbols to the library that include a mounting pin. This pin would get a special pin number (Example “MP”)
This would double the number of connector symbols in the lib. It would also mean we would need to add some suffix to footprints that have such a mounting pin to allow correct footprint filtering.
The discussion over at the library repo: https://github.com/KiCad/kicad-footprints/issues/117