What if, all the details for a rellie are correct but the place of birth is on the next line down ? 
Mackiwi
Hi
Yes, very annoying, but you still cannot alter it. I found one of my husband's possible rellies, listed as head of household and aged 14. Not impossible, you might say, but he was living with his mistress, it says he was married and he's a brewer's carter. He has a son aged 5 and a daughter aged 2. Now that is very precocious!
The enumerator SHOULD have written age '41' but I TWYS just the same, even though I knew it to be incorrect.
If you alter what you see and YOU know your family information to be correct how, then, will the rest of us know that what we see is the original information of that page?
We could all do it, as we type out the page, putting in that bit of info that we know but which is not what the enumerator put. WE might be getting that bit of info wrong as well!

Could be very misleading. So if you TWYS then its no-one's error but the original enumerator's.
Transcription errors, well... IF they are genuinely wrong, there must be some way of contacting the 1901 Leftovers site and asking for it to be corrected. On FreeBMD they allow a search of that particular page which the entry is on (the pair of spectacles you see beside the entry) and if you see something the volunteer missed, then you can put in a corrected entry notice, the website then contact the volunteer who then changes it and it is corrected on the website. I think I've done about 4 corrections in 18 months.
But they do ask for proof of where you saw the original entry.
Hope this helps a bit.
Best wishes
Claremcg