I agree that, whatever you want to call them, those locks are very useful, especially for a utility bike. Frame lock is a good descriptive name.

I was the one that mentioned recumbents on the Canadian  prairie. That was my first introduction to riding with highly skilled bicyclists - several of them had ridden Paris-Brest-Paris multiple times -  on recumbents. Later, I acquired recumbents for my own riding. I agree that recumbent trikes can be dangerous 'if you put a foot down at the wrong time, but recumbent bikes are not. I no longer ride clipped in on any bike and, I have ridden tens of thousands of miles on SWB recumbents with 20" front wheels. My feet have slipped  off the pedals accidentally many time and never hit the ground. The pedals are, even at their lowest position, about 20" above the ground!

I've  ridden several times as many miles on my upright touring bikes as on my recumbents and am very comfortable riding them, but they have never been as comfortable as my recumbents. Now, like those recumbent randonneurs, I can no longer do long rides on my upright touring bikes because rough roads are too hard on my neck. 

Hi Mark

Thanks for your message.  My recent experience was following someone on a recumbent bicycle on a winding downhill.  He encountered an unexpected obstacle, put a foot down, and ping, a broken tibia and open fracture.  Even before that I found it scary to watch him especially getting started.  Still, he is 75 and tough as old boots, recovered enough to ride but not walk, and out on an upright bike.

I'm no expert on recumbents, but that incident confirmed my dislike of them.  

They clearly suit your present needs, and you are far from being alone in liking them.

Oh, and frame locks make a useful handbrake too, when required.