I had this happen twice with a Spyerco Sliverax, and it's a shame because I otherwise loved the knife. The combination of the flipper tab with a notoriously weak detent meant that my phone could tap it open even when clipped against the side of the pocket. This unfortunately stopped me from EDCing that knife. Perhaps I'll find someone to grind off the tab. Right now, I'm EDCing a newly released Kershaw Lauch 13. I really love it mostly due to the light weight and style, but it has the added perk of locking closed as well as open until you actuate it with the pushbutton. If your local laws allow it, could be worth checking out.