Bizarre that someone would use the Internet for forums and sharing information but won't entertain a mobile incase THEY track him 
When I use t'interweb, I'm in one of only two or three locations. 'THEY' could find me easily from that or other information. When I'm out and about, I make sure 'THEY' have to try a little harder.
Good luck travelling without documentation on a phone/QR codes etc.
Have read, in preparation for my escape, that printed docs aren't being accepted in certain situations due to TCV transmission. 
I'm not talking about traveling without documentation. For France, currently, it's Passport, Declaration sur'lhoneur, and Covid Pass QR code. All of these are acceptable in printed/hard copy form. The rozzers don't care if they scan a QR code from a phone, or printed out. I believe you can also register your English NHS QR code into the French Tousanticovid (TAC) system, and that gives you a 'French/EU' compatible QR code acceptable in other EU countries (and CH). The French QR code is valid for 9 months.
The NHS website talks about downloading your certificate to a 'wallet' on your iPhone. You could then turn off international roaming. So what's the difference between a printed copy, a PDF on a PC, or a whatever stored in an iPhone wallet? None of them are dynamically updated.
And what's worse is that people have realised that you should download your current certificate before you get tested - if you need to get tested for any reason. Why? Because if you test positive then your certificate is suspended for 21 days, even if you are double vaxxed, so you can't travel. However, if you've got the old certificate stored off line then.....
