You have to be careful about all sources. And even things written in stone aren't necessarily written in stone. I was just working on the profile of Santford Albery-43. I used that spelling of his first name when I created his profile because it's spelled that way on his gravestone in large letters. But having entered 9 other sources (7 censuses, his DC and a marriage record,) All of them spell it Sanford. so I suppose I now have to change his GNAB and have the Santford spelling as a varient, if prominent, one. If I run across a birth record for him I might have to change it back, however, since not all sources are equal for a given fact.