Welcome Chas.
LTSO - I agree 100%
In general, scratchbuilt and custom recast = good (this would include add on kits, extra details, etc)
Straight casting = bad.
All that said, model builders often cast something they need when building a model for their own use. I think Chas is offering to supply an extra part or two for someone who has lost a piece, or doesn't know how to cast. Thats a nice offer. Lets not upset Hasegawa recasting their work for sale (not that it would be economically feasible) but I don't imagine they would have a problem with someone enhancing their kits with detail pieces or someone helping a customer stay happy by helping replace a lost piece.