Not sure if I'm misunderstanding what you're saying, but I tried to buy some blackcoins a few days ago on CR and I placed my buy at about 4k sat, and it never filled because the price went up and I didn't update it. It had cracked 4500 the last time I checked it. So I believe the price was over 4k satoshis, legitimately, before any of this happened.
What do they gain from doing this?
are you seriously asking this on the internet? If so welcome, it must be your first day.