Hey man, that's not a poll!
But, I'll answer anyways. I always remove the hitch when not in use. I've banged my shins on too many tow hitches in the past.
I use the standard pin and clip. I tow my boat from storage to the water and vice versa in the fall. I rarely leave the boat hooked up to the truck unattended, so theft is not a big concern for me.
If I were trailering and leaving the rig in public places overnight, I would definitely consider a lockable hitch.
For the extra few bucks, I would get a locking hitch pin rather than a bolt.