There are reputable casinos that aren't afraid to show off how their bonuses and events draw run. They do it through live streams or post the winners in their community. When it comes to new casinos, I don't think streamers are reliable or even providing real or trusted results because they can fake it since they are being paid and their main goal is to promote the casino to attract more players. New casinos would fake even their transparency to gain the trust of most players.
Duelbits is one of the few reputable casino that always deliver a fair and transparent draw to all their giveaway. They always announce their winner to the public same with their grand event like Christmas and Easter Giveaway that always being drawn live with the use of livestream. In fact there’s already some user here that manage to win on live draw on previous giveaway.
I encounter casino that do the shady draw for the result and most of them are just new or they don’t have a decent number of players that makes them so pathetic to cheat their own giveaway.
I have seen many forum users who won decent amount from DuelBits giveaways. User "wish" has won $10k raffle during Christmas giveaway few years ago, I have watched the live stream where giveaway has been managed by popular streamer. Tbh, it is based on the luck and winning raffle only takes one ticket. Few reputable casinos offer provably fair system to verify results but it is not as random as live draw, IMHO.