I honestly wouldn't say anything. The person will just take it wrong. Most of us who have wanted yorkies, have wanted them for quite awhile...while looking at pictures of puppies all over the place. You can tell when looking at a picture of a yorkie puppy if it's what you think of as 'standard' or even 'in the normal range'. Some people like a different color yorkie. Except for brewiers and parti yorkies, most don't have that much white on them(I saw a picture of a puppy with white on it's face...it is quite a bit of white and I had never seen white on a face as a puppy before this, looked more beagle to me than yorkie). That doesn't mean someone else won't want it though.
However, you just have to assume that the person looking for a puppy has done a little research. Even if they haven't, it doesn't mean they won't love the puppy anyway. My opinions of what a yorkie should look like don't match everyone elses. I thought I prefered the blue/gold color until I got my little silver/tan baby so go figure
It's nice that you were thinking of a way to try to protect someone out there. Hopefully the person who ends up with a puppy like you're describing doesn't end up being too disappointed. I think when you pay that much for a pet you should get exactly what you're looking for, it doesn't always happen that way though.