Out of sight has been my security method here. My 2KW Honda Generator sits secured in the tailgate corner of my hard plastic folding bed cover. This all locks up when not in use.

When we need to use the generator we just pull it out onto the dropped tail gate and connect up the shore power cable.
We never leave our generator at the camp site unattended. It goes where we go.
Been sitting in the back of my truck since 2008.
Most of our camping is with our OFF-ROAD POPUP camper usually way back in the woods somewhere. Its beginning to even start looking bad back in the woods now with strange two legged creatures running the trail roads.
Roy Ken