They are just covering their own asses in case the SEC decides to come after them for operating an illegal exchange. Since they recently decided that ICO tokens fall under the class of "securities" the government has been scrambling to figure out the next step. Exchanges are scared cuz this could mean big changes for them in the future. Bitfinex really bummed me out with this decision because that is my primary exchange. Gonna have to move over to Kraken or HitBTC now to trade my EOS tokens.