If you have time and some basic shop tools, you can do what I did with my Honda 3000.
I am carrying it on front hitch and obviously did not want it to get stolen.
So using parts from one of those cargo platform, I cut the tubings to make short frame under the generator legs.
My generator had rubber pads with metric bolts going from the bottom, up to generator frame.
I match the holes in the tubing and in new tubing frame, I drilled big holes at the bottom and smaller to hold the bolts on upper skin.
So the only way to get in/out is metric socket.
Having access on top of generator legs, I add extra nuts to hold the vibration.
Having plastic caps for tubing end, I also inserted pieces of wood inside, so you can't see the bolts.
The whole platform holds to front hitch with locked pin.
So in case somebody would like to steal my generator, he would need at least 1/2 hr and metric sockets to figure out how the things holds.