You poop and I'll pop!
I based what I said on what I heard in a D/G melodeon workshop where the tutor gave this rather awestruck mystical half-whispered phrase "and then you'll be crossing the rows" - oh my gosh! A bit of tongue in cheek then.
In my very first lesson on the B/C, I learned the scales of C, G, D and A. Apart from C, they all require you to use the outer B row, but it was never referred to as "crossing the rows". So let's calm down and not get into another Mudcat row, please! Your final sentence GSS is fine: agreed.
And of course, I play tunes in whatever key the majority go for, which does mean a lot of D and G.

Re what Noreen said, the rare occasions on which I might play in the key of B major, is when a singer happens to choose that key, and then asks for an instrumental break between verses of a song - yes, quite rare indeed!