I've seen few projects that decieved investors into thinking that they will list on binance or okex and Kucoin without these exchanges confirmation, my advice is once a project claim they are going top exchange do not hesitate to go to the top exchange social media, if the listing is legit the exchange will atleast say something about it. Wise up
I have seen some project announces their partnership that turns out to be true, and some projects that just use the exchange to get the attention of the investors, either way, investors and bounty hunters should investigate if there is truth to what they are promoting, but yes you are right sometimes exchanges also announce it, to help the project take off in their crowdfunding campaign.