For instance, Rolan could be lying about Lorroakan even existing. But when I see a Baldurian tag saying something like "I've heard of him," then I know Rolan isn't lying. Well, Rolan could be lying about having an apprenticeship with him, sure, but I know that Rolan isn't just making him up altogether out of whole clothe.
Well ... i dunno where are you from, but in Czech we have one historical person so famous, so almost litteraly EVERYONE has heard about.

His name is
Jára Cimrman.

Funny thing tho, he never even existed.

You know what i mean?
Sure, even i doubt that Larian would create imaginary Wizard just for the lols ... even Gale coments on him, so this is almost certainly not the case ...
But the point is, just bcs you have "heard about somebody" doesnt really mean anything.

Sure, you can argue that I should role play not having that information.
Yup.

If I'm not Baldurian, I don't want to see a Baldurian tag in my dialogue options.
Im quite sure there will be some tag removal mod at least ...
And i certainly do believe it would not be too hard for Larian to allow us to simply remove the tag oureself while creating the character ... but i hardly doubt there will be any other tag to pick. :-/