I have found a solution for when you plug your headphones in to your device so it doesnt activate siri whenever you plug your headphones in
It is really easy for what you have to do...
First go on to settings>General>Spotlight search
Then at the top it will say siri suggestions you will have to turn that off and if you scroll down you can turn them off for selective apps you wish to turn off.
I Hope this helps.
iPhone 5c, iOS 9.2
