They don't suspended as a knee-jerk, spur of the moment thing. They do actually investigate the situation and, when they find activity egregious enough, they suspend the stock in order to put a stop to the illegal activities.
In this case, CRCW was suspended for fraudulent activity including:
" concerns regarding the accuracy and adequacy of information in the marketplace about, among other things, the compensation paid for promotion of the company, and statements in Commission filings about the plans of the company’s insiders to sell their shares of The Crypto Company’s common stock. Questions have also arisen concerning potentially manipulative transactions in the company’s stock in November 2017."
The regulators KNOW these activities have taken place and are true. Especially FINRA, as they found the infractions and referred the evidence to the SEC, who found them serious enough to require a suspension in trading to stop the fraud.
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