One concern I have is that if I were to record unconstitutional actions by police, would my phone be seized and the videos erased?
One solution may be to record via internet stream. Then they would have to also think to take an extra step of checking for the software and logging into your account to delete your videos. Meanwhile, you could call someone from jail and request they copy the video before it gets deleted.
I recommend that you keep your recorder software signed in and ready to go and use quick locking/unlocking on the phone itself.
Even so, I urge you to comply by all written recording laws. This advice would only apply for situations where it’s not technically illegal but which might happen anyway. After all, they’re acting unconstitutionally in the first place! – C.D.V.