I couldn't agree more with you YorkshireExile. At a stretch, and I mean, at a stretch, it MAY be relevant to such tests as quantification and titrations, where you are giving a result involving a measured number, ascertained with red cells that may express different numbers of antigens, which may themselves involve protein or carbohydrate substitutions, but that is all.
How on Earth your inspector thought that this was remotely relevant to blood grouping, with all the positive and negative controls used to ensure the antisera are working properly, and the temperature mapping of everything these days, like you, I cannot see the point. Either he or she was trying to justify their position as an inspector, and/or was going well over the top.
I would be amongst the first to say, very loudly, that Quality in the world of Blood Transfusion was pretty low at one point, but now, there are times when Quality issues actually interfere with the laboratory doing its job, for no good reason, and this seems to me to be one.
END OF RANT.