I've seen some new casinos before that didn't thought of applying a wagering requirement on free spins bonus. Withdrawals were fast and easy during those times and KYC was still not mandatory. Users would create multiple accounts to use the free spin and wuthdraw what they won immediately. After few days, their website can't be accessed which likely they got bankrupt because of a loophole on their promotion.
Companies run marketing programs for getting positive effects and growing up their business more including income and profit. It does not make sense to run any marketing programs while knowing it is best way of burning money. To reduce risk of money wasting and burning by lack of experience, companies must be careful by referencing terms of marketing programs run by other companies as well as how to detect and disallow cheaters.
Having clear and well defined terms against cheaters will help them avoiding mistakes and so maximizing effects from marketing without damage on their company fund that can be used for many purposes, not only for marketing.