Well, I'm not going to tell you how to disable a safety switch. That would be "bad". Although, my L3410 does not have a seat switch at all. I can't tell you the number of times that I have operated the tractor standing so I could see what I was about to mow over!
Now, if I were trouble shooting a switch, I would unplug it. Then put an ohm meter on the switch and see if it is normally closed or normally open. If it was normally closed, then unplugging the switch would open it just like when the switch was operated. If it was normally open, then putting a jumper wire from one terminal of the plug to the other terminal on the wire from the tractor would make the switch look like it was engaged, even when it was unplugged.
Of course, when working on equipment with interlocks, a well placed tie wrap can make a switch stay down...That is done often to trouble shoot equipment.
I am NOT advocating you to bypass safety devices. You are on your own! I am not accepting any liability for your foolish actions. IF you make the choice, it is your action and your responsibility.
jb