18. Flex Frac Logistics, L.L.C a nonunion company delivered frac sand to oil and gas well locations. The rates it charged were confidential so it required employees to sign a nondisclosure clause prohibiting employees from sharing confidential information outside the company. The information included "our financial information, including expenses or costs and prices". After Flex Frac fired Kathy Lopez, she filed an unfair labor practice complaint with the NLRB, alleging the clause prohibited employees from discussing employee wages. Were employees free to discuss the terms and conditions of employment outside the company