I found some isolated panel-mount BNC connectors which have an integrated capacitor for RF chassis-bonding, e.g. this molex part 73100-0090.
The datasheet contains this simple schematic to illustrate the connection of the terminals:
Obviously, the capacitor connects between the shell and the grounded parts (posts and compression clip).
But how is the pin electrode (A) connected in this scheme?
Image and 3-d view available here: