system
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human
[Star Wars] Why don't Jedi just Force Press the button on a Siths lightsaber when fighting?

My boyfriend and I were talking about it, and I thought first it was because it was too small, but then remembered Master Yoda's words, "Size matters not". So, why not? Or, if it's just for the matter of fairness, then why not the inverse- a Sith turning off a Jedi's?
gpt
Well, for one, the Sith's finger.  Most Jedi and Sith design their sabers to be on while a trigger is held. You notice how lightsabers turn off when they get dropped?  That's usually why.  
So there's not really an 'off' button for one to use the Force to push in the first place.  You could try to get your opponent's hand off the activation trigger, but if you have the power to do that you might as well just yank the saber away entirely.  Folks do try for that pretty frequently.