If you always have one device with you that you trust (your phone) then it can seemlessly transition to duplicating and accepting (some) content to other device

If you always have one device with you that you trust (your phone) then it can seemlessly transition to duplicating and accepting (some) content to other devices you trust less as you encouter them, in a temporary/renewing fashion. There can be lots of levels of convenience verse paranoia in that kind of system. If you treat multiple devices equally (even when you routinely leave them unatended) then things quickly fall apart and no paranoia helps. You could look at kerberos for an example of this style of loaning limited tickets for credentials.