What you and other ppl are saying is correct on the physical world or when tossing a coin..
However, RNG is not working according to the physical laws.. In gambling aka RNG, you could have huge discrepancies in the results, meaning you could have lot of failed consecutive attempts and then lot of succeses.. What matters is that at the end of a cycle, which could be even a billion of attempts, the nominal percentage is reached..
I am not in any way defending NC or saying that this is what they actually do or they should do, because i don't know.. I am just saying what really happens with RNG/gambling products and to me as a player this is how the events in l2 seem to be working like...
My opinion is that this is a game and shouldn't be a casino and more importantly a very expensive one.. I mean there are events here where you can gamble with 500 dollars and get nothing.. This is as close to a scam as it can be if you ask me, and despite that there are ppl who do try.. Add to that, that casinos are being audited and monitored by authorities so more or less they do follow some rules, which is obviously not the case here..
And by the way, there has been some improvement in prices and events over the last few months, but there is much more room for more imo...