Short-circuit in CAN lines
Those are worst case short circuit currents. If something breaks and the CANL pin gets directly connected to 12V supply voltage, maximum of 200mA can flow when it tries to drive it low. And the other case, if CANH gets connected to -7V, max 200mA can flow. Wires must handle at least this current. Surely most small signal relays can switch 1 or 2 amps, 200mA is nothing.