You know, it never occurred to me that this is a feature that would be widely needed.
I could never be comfortable having a seat that didn't require a key. I keep too much valuable stuff under there. I'd be nervous about it every time I left it.
Please don't keep anything valuable under the seat of your bike. That thing is way too easy for a crook to pop open.
I keep a few things under my seat such as Several Hats, bungee cords, rags, flashlight, tire gauge, tire plugs, ride-on, air compressor, safety vest, flannel shirts, face shields, insect repellant, WD-40, Lots of Tools, Flask, Safety Reflector Triangle, Folding Cane, First Aid Kit, Lighted Traffic Director Light, Bottle of Motor Oil, Bottle of Antifreeze, Rope, Dog Leash, Tape Measure, Duct Tape, Tie Wraps large and small, some LEO stuff and a bunch of other stuff that I can't remember right now. No guns or ammo or knives (I carry all that). Nothing that can't be easily replaced.