locking the jaws on the hitch

OK, I am new to towing a fiver so I have a question regarding posts I have seen in the past. People talk about locking the hitch jaws so no one will open them when they are stopped for awhile. My question is, how does someone pull the handle to unlock when the weight of the trailer is on the hitch. I have a Hijacker hitch so maybe it is dependent on what hitch you use but there is no way to pull the handle on mine when the weight of the trailer is on it. Are all hitches this way or is it an urban legend (like the guy who was trying to siphon gas from a MH and siphoned from the black tank--impossible since there is no way to access the black tank from the side of any rig.)

The only way I see to do this is that someone would have to lower the landing gear to take the weight off the hitch, unlatch the hitch and then retract the landing gear again.