A little strange and something that cannot possibly happen, I have never encountered things like what you mention here, in the end the deposit is the main requirement that is required, what is offered by the bitcoin guide.org website, at first glance I didn't find anything like what you mentioned, apart from a few gambling sites that I saw here.

To be honest, I have seen several websites that suggest free bets without anything and also tempting offers such as promo codes and several other bonuses, in essence, play as much as you like and win millions of dollars, without a deposit and without placing several rounds in the game that have been determined, you can't do anything.

I don't doubt the bitcoinsguide.org website like what you are talking about, but I'm not tempted to try.