Yes, it's unfortunate that there will always be individuals who try to take advantage of promotions and giveaways. It can be challenging for an online casino to differentiate between genuine gamblers and those leeches and scammers who are just looking to scam or take advantage of the system. But they should at least try their best so that they don't lose money on them and instead attract more real gamblers.
The unfortunate situation about all that is;
These leeches as you have rightfully called them are always the first to make a loud noise should they happen to be subjected to some investigation. As unfortunate as the situation would be, it never stops the investigation process.
The casino has got to protect itself somehow and they've got the terms to help them do that as gamblers are often on the look out for what they can exploit. That's why Neodice.com has specifically spelt out that, there aren't or shouldn't be any third party registration excuses on the part of customers in its terms.