That's interesting. I've never encountered a 1 that looks like 7 in handwriting. Usually it's I and l that mess with 1. In what style of handwriting is 1 similar to 7? I'd imagine the top bar on 7 is a sufficient differentiator.
Here's a deep link to someone in Germany writing down what visually looks like "77.5 :7:7" but his narration says it's actually "11.5 :1:1"
But this thread reminds me of when I lived in Canada for a while (coming from France) and I did misread numbers very often, which was totally unexpected to me. Yes, 7s and 1s looks very different between Canada (and the US I guess) and France (and probably the rest of Europe).
I haven't had this problem with Belgium though I'm not surprised if the standard here had been chosen to be the same as in France.
I was just saying it was obvious to me and it even takes effort to see how they could be misinterpreted. But I know they can be.
so 'muricans mistook my German ones for sevens, all the time, and I had to force myself to write what looks like a pipe symbol vertical bar to me instead of my trusted one.
and to disambiguate, we cross the seven like a lower case eff or tee is crossed.
I'm English, and I can't honestly remember which country it was that I've lived in (I think France...) where there were a couple of numbers that even after living there for a year I still wasn't confident reading when hand-written on things like café menus. And I don't think I would have thought of that being a systemic issue rather than just blaming an individual's handwriting before I lived there, despite having taken over 100 trips to France before moving to live there for a year.
I was born in Europe so I put a horizontal line midway through 7. But now I'm in Canada and nobody else does. It can be a really tiny angular difference between a 1 and a 7 for a lot of people! :)