Further reply:

I was contemplating this exchange and wondering whether Gall's Law has any value (constrains expected experience).

I think it does. If an engineer today claimed to have successfully designed an Albucierre engine, I would probably execute an algorithm similar to Gall's Law and think:

The technology does not yet exist to warp space to any degree, nor is there an existing power source which could meet the needs of this device. The engineer's claim to have developed a device which can be bound to a craft, controllably warp space, and move it faster than light is beyond existing technological capability. We are too many Gall Steps away for it to be probable.