The assumption you leave unstated is that it is unsafe to have your phone searched by the government. While that's a point of view I consider true for many, and I endorse halting warrantless border searches of phones, it is certainly not true to say that phone searches are unsafe for all.
I know what you mean but I think the opposite: It IS unsafe to have warrantless government searches on your phone.
Once people get used to that what's next? Since we have your phone open, just go and pop your Gmail credentials in there for us why don't you? Your phone was in your pocket so what else do you have in there? Keys, what do they open? etc...
It's a slippery slope and the reason we have checks and balances.
