I don't see how releasing the mainnet client would mix with the exchange selling IOU tokens. The mainnet would not interface with yobit or anyone else selling IOU's. There is no real network connected to the yobit waves market it is just a fictional wallet they opened with X amount of tokens. Depositing and withdrawing from them wont work. There is no deposit or withdraw options for the people buying wave tokens on yobit.
THIS, people need to learn to read, Sasha SAID: Yobit will not be getting full node source code.
If you don't understand how something work, don't try to explain it to others. IOU's are nothing new, Yobit has purchased 100 BTC in the crowdsale, just like they did with Lisk. They will release after Waves is public live. I don't recommend buying there obviously, mostly cause Yobit sucks ass.