Even Disney was engaged in stealth marketing, so I wouldn't be surprised at all if a less reputable industry such as gambling is engaged in stealth marketing.
Disney Puts Some ‘Frozen 2’ Promotions on Ice After Twitter Flap https://archive.is/RFsLV
Disney Puts Some ‘Frozen 2’ Promotions on Ice After Twitter Flap https://archive.is/RFsLV
From your link:
> In the U.S., the Federal Trade Commission said in 2017 that influencers on social media sites such as Twitter and Instagram “should clearly and conspicuously disclose” any paid work to promote a product or service.
Sponsored posts should be clearly labeled, at the very least