Maybe I am the crazy one but there is no way I am going to chain it to my truck, unhitch, fold the tongue, remove the pin and lock it. Might as well just remove the whole coupler/actuator at that point.
Just throw a lock on and go to sleep. Any trailer coupler can be locked to a ball easily. Leave it attached and throw a cheap lock on. I'm with @Orlando76 I pick my parking spots for security, not a lock. The lock just removes the opportunity crime aspect.