strave, I do the same thing in regards to filling an order. If I cannot fill it all at one place, I will see if I can fill it at another taking into account shipping and total price.
My beef is when a place knowingly gouges on hard to finds. I saw it for years in the cigar world. Opus X, Anejo's, Don Carlos, Padron Anny's were all impossible to find at one point, certain retailers when they had them, jacked up the price knowing people would pay it. Well look at them now, not a one of those cigars is hard to find anymore and many of the retailers that did gouge are gone as well. To me it is about respecting your customer, not trying to ring every last penny from them.