Still a big old nope. No one taking the effort to pump would put that milk in a creamer bottle. They wouldn't add to it through the week, human breast milk has a very distinct smell, and being non-homogenized it separates (in my experience in less than a couple hours to a very distinct and solid cream layer that essentially sticks to the sides of a plastic bottle until warmed and the less fatty remainder) there is no way someone would look at it and think it wasn't off (again, not that they would because it's just a note and that lady is just saying it to get them to stop, not actually wasting milk by doing this)
I was always afraid to try it after my wife's pregnancies, but after the last one I did give it a try and it was really really good. Apparently, there's also some kind of emotional bonding mechanism and my wife enjoyed that very much too.
I'd drink that