I would hope that with an online catch recording system, it would be connected to a database that can be accessed by DFO officers. Now, if you’re in an area without cell coverage, it wouldn’t update immediately, but otherwise I don’t see a reason to hand over your phone so they can cross-check your catch logs to your name and angler number. Either way, if you have a smartphone, any social media accounts, or even a personal computer, your personal data has been collected and sold a million times. Not sure the tinfoil hats are necessary with respect to the government, considering the existence of things like drivers licences, SIN cards, etc.