Accidental press would be caused more by the under-differentiated icons than direct access to the buttons. Right now it has small lock/unlock icons with letters and in the same color so it always take a beat to see which one is which, making the current widget very poor in user experience.
Think of all the steps to use it.
1 open widgets panel. (scroll to widgets if on notification panel)
2 click sesame to reveal buttons
3 take a moment to see the button you want to use.
4. press the button
5. wait for sesame app to open. unlock the phone if locked.
6. wait for the connection and execution.
My wish would be to eliminate step 2, 3, and 5.
You can have bigger icons in color so that it's very clear which one does what, and I would favor unlock button over lock thanks to auto lock feature. I think this will reduce the steps and get rid of confusion. If green and red icons are not your style you can do solid unlock and outlined lock icons instead, but do differentiate the look so that you can tell them apart in a quick glance. I don't think you need tiny letters saying lock and unlock because icons will do the job of conveying that information. It'll soon become a muscle memory to use it and look how much space you'd save on the widgets panel.
And to skip step5 sesame should be able to operate in the widget so that user won't be kicked out of the app they were using. I understand current behavior when the phone was locked so that user would have to authenticate first but if phone was already in use there would be no reason, and since you allow knock knock to unlock without authentication I think it's ok to offer the option of unlocking in the background.
And this kind of elimination of steps is the key. (no pun intended) Sesame has to become more invisible to users and should seldom require to open app or even widgets because it just works. I think IoT devices like Sesame should be more like internal organ. You need them to be extremely reliable yet you never have to think about heart to beat or command liver to detox chemicals. When users don't think about even forget the name of the sesame because the door seems to know what to do all the time, you'd have done your job. 
