If it's a perfectly working card, with no signs of damage, and all the gubbins in the box as normal... I doubt it would bother me. There must be a lot of customer returns which are in *perfect* condition.
In fact the DSR law is a pretty bad law in my book. "Buyers remorse" should never have been codified into law.
But as it stands, stores have to sell returns as B-grade and not new, so you don't have to worry about it.
it would bother me a lot tbh...if i paid for a new...and got a second one even with full warranty ....
but as you have said there sold as b-grade is fine...and you know before you purchase...