1.3m from a 50" sounds a bit daft. Some of the specs seem to overdo it and assume you're a 'front of the cinema' person.
For TVs I think a lot of it depends on preference and usage, whereas for projectors people do want to have more immersion in films, and so tend to sit closer to big screens. Some want a small unobtrusive TV.
I watch a 26" TV from about 2.8m, and it's fine, (plus I can also see the HD difference, (even though it's HD ready 768 rather than 1080), which if you look at the figures the experts reckon I can't). This was bought before we moved, and though it's fine, I think if I bought for the current room I'd go 32" perhaps.
I have to add though that this is in additon to a projector, so I'm not film wathcing on this. The projector I now sit aqbout 2.6m from a 1.6m wide screen, (72" diagonal approx), and this is good. I'm a towrd the rear kind of cinema person, so this is a good balance of immersion and seeing the whole picture for me. I have tried slightly bigger at that distance, (about 180cm wide), which was good, (no better really though), but not as convenient, and much bigger, (about 2m wide at 2.9m at previous home).
Even the 2m wide wasn't too overbearing, and it certainly gave a big cinema feel, but wasn't a goer in the current room, and though I dind't find scanning an issue, I think it was maybe a bit too wide; I get more of a sense of the whole scene with the current set up.