From my trip to LA, I’ve seen several of these water control valves placed above ground. (Must be nice, in Chicago, these guys would turn into ice and destroy themselves).
An oddity is the choice of security — a wire mesh that stops folks from disabling the water. This could affect fire systems, but those usually have a standpipe or external outlet for sprinklers, but what this can mean is — when your coworkers are coming back from the company Chipotle outing, they can’t evacuate the sinister remnants effectively.
The cages are a minor obstacle, since these are quarter-turn ball valves, they only have to be rotated 90° in order to turn off (or on) flow.
Inserting a stick, pipe, or some other rigid instrument and biasing it against the wire cage would create plenty enough of a lever to force the valve shut.
Solution? Lock the valves like everybody else, except this water main, since it uses a hilariously deficient “warded Master Lock” that can be trivially bypassed in several ways (shimming, warded picks, keys that accommodate wards, etc)