There is only 1 safety switch that is really needed to protect others not the idiot owner.
If some one is stupid enough to shove their hands into the deck with the blades running then they deserve what happens.
Ditto to running over live power wires laying on the lawn. Nothing like proving Darwin correct.
However without a seat switch, a mower can run away should the driver fall off and in this condition can run into other people, animals, through fences , onto roads etc etc etc.
Thus injuring other people.
Now this may or may not be possible in your situation but never the less , dissabling it is stupid.
I have a customer who fell off , chased the mower ( cruise control ) then managed to loose 2 toes trying to get back on rather than just switching it off or reaching out & depressing the brake pedal.
I seem to remember suggesting several ways to extend the plunger's reach all of which would have achieved your goals without jepodising the safety of yourself and those in the proximity of your mowing.