Let me preface what I'm about to say by telling you I can say this from a breeder's perspective. I understand that some of them get under a LOT of pressure. Once upon a time I was a breeder of working dogs (different breed than Poodles). I had a very long wait list. I had people making demands. I had people pleading, offering me bribes (double & triple puppy price) to bump the line, skip the line, choose their puppy before everyone else. I fully understand the temptations to allow the buyer to drive the bus... here's the thing. Before I bought my first dog with the intention of breeding (believe me I put the time & effort in prior to embarking on that journey) I made up my mind that my dogs & my puppies came first & I would not allow $ to drive me into doing anything wrong. So what does that mean? I wanted to set up not only the puppies for success but the owners/families who ended up with my puppies. Keep in mind I had working dogs who protected human life by force when necessary & some of those dogs lived in homes with infants, toddlers, elderly people, etc... so that meant extreme care in the selection & placements of puppies. When you have working dogs there is always a guy who wants the biggest, bst, toughest, alpha-est pup in the litter. And with maybe 1 exception in my years, these are generally the men who can not handle the biggest, baddest, toughest, alpha-est pup unless they abuse the pup & turn him into a monster or break him into a scared dog which is actually more dangerous. Part of a breeder's responsibilities is to protect buyers from themselves. They don't live with the puppies, I did. I knew my puppies intimately. I spent hours sitting, observing my litters. I knew the dominant pups, the mild pups. I knew which pup was going to be a little difficult when it came to male/male or female/female encounters with other dogs.
You can NOT do this at 2 days old or 2 weeks old. Can...NOT...be...done unless God himself is telling you so. Puppies' personalities develop & even 6 weeks can be debatable. I've had pups that I thought, "Okay that's the pup for the family with 3 sweet little kids" but by week 7, I'm telling them..."nope, I thought I had the pup but he's going to be a bit much. I do however have a female who would be perfect. They didn't want a female (which was okay by me, as I would refund their deposit, this was NOT their fault) but the family wanted to meet the little female & it was love at first sight. She went straight to their daughter & lay on her back like a baby. She licked the little girl's face & any time she would get approached by another puppy, she would get up & run her sibling off. This was HER kid. While the parents debated, the little female ended up wearing a doll bonnet on her head & a ribbon around her neck & she pranced around with her new puppy-wear like she had been named Queen of the world. She was a perfect little lady with everyone else & they later told me she was the best dog they've ever had. THIS is why you don't allow or force people to choose puppies based on color or based on an early look. Had I allowed the "lock in" of this male pup for them that was everything they wanted except temperament & personality... totally wrong for this family. Their kids were the sort who read to the dog, who played hide & go seek with her, who were just gentle gentle children. On the flip side, the male they thought they wanted went to live with a household of rough & tumble boys, who spoke his language & he was a champion football thief. The parents told me they never had such tired boys because Hercules would steal the football & make them chase him & by the time it was showers, homework, & then bedtime... they were all pooped (boys & dogs). MUCH better fit.
I would not put money, time, or faith in a breeder who was insisting I make a choice like that at 2 days or 2 weeks on a dog who would become my family member for the next 10+ years. I understand being pressured by new puppy owners who want to know which pup is theirs but doing the right thing for everyone involved is far greater than what happens when you allow this & you end up with pups in the pound, being euthanized, & your reputation is in shreds because you allowed this. I've been on both sides... this is my opinion