How can the gamblers verify that the actual amount of people are receiving the drop or the bonus, if there are no list to verify it?
This won't solve the problem because even if the casino publish the list of winners, there is no way to verify that those winners are real users and not just bots or fake usernames.
To make it as transparent as possible, the casino can partner with a reputable streamer and ask him to draw the winners on a live stream
or use a provably fair system like giving each user a ticket number and use the blockchain (transactions/blocks hashes) to determine the winners.
Hmm, I think you guys are taking the drop features on casinos too far, one thing I believe is that the drop which happens in casinos chat box was never designed to be something really important, or a kind of giveaway that should really matter, drops are designed as a way of rewarding users who spend their time on the casinos chat box helping other and probably sharing ideas on what to bet and game to play, it is also a way of encouraging other users to become and stay active in the chat too.
Taking the drop to YouTube or which ever platform the stream is to happen, will simply kill the purpose to which the drop was introduced in the first place.