Same as with everything else in life, the people doing that are going to run the gamut, from the lazy basically con artists to the OCD mfer that's a pain in the ass to work with because they're so meticulous about everything. One trip at the store isn't going to tell you if which of the two extremes (or somewhere in between) the grower of a particular strain is, but repeated use of a particular strain will either be consistent, or not.