Connector's placement - EMC
The connectors themselves aren't good antennas, but there is an assumption that long wires will be connected to them.  They may or may not be shielded, but in most cases each conductor is likely longer than your whole PCB.  To protect your circuit from absorbing/radiating through them, it's best to designate an area of the PCB for connectors, clearing out even the ground plane (which might pick up external noise) and filtering each line at the border of the shielded area.  Feedthrough filters are excellent for this purpose.