Likewise, I've flown more in the last year than in the decade prior and every single leg my Flipper has been in the side pocket of my backpack. Never once has it received even a second look from the TSA, including also DEF CON.
I agree, but it's also a rather distinct device so if it were being intentionally confiscated by TSA as some of the upstream posters claim it'd be really easy for them to identify. If it were policy in any way, even the most basic object recognition systems attached to even a simple x-ray scanner could identify one with ease.
That's of course not to say some rogue agents haven't confiscated a few Flippers, especially after seeing hyperbolic media reports about them being magical evil hacker devices, but I have high confidence that there's no official policy to do so.