The overwhelming majority of online casinos are on the up and up, nonetheless there have been cases in which some websites have been suspected of having fixed their gaming software so that they enjoy and even greater advantage. For instance, a casino's Random Number Generator (RNG), the pre-programmed mechanism that ensures fair play among an online casino's slot machines, blackjack deals and rolls of the dice could be manipulated to payoff less than that casino's advertised slot payout rate, and of course to not deal decks of cards randomly, perhaps loading decks with small cards that give the online casino the advantage. Again, this is rare but it does happen.
Another form of cheating by online casinos is carried out by some very short-sited online casino companies. These shady operators have a tendency to either drag out how long it takes for a player to withdraw cash from their casino account, or prevent them from accessing their cash at all. These "slow poke" websites tend to do this with the mindset that players will simply continue to play, and wager, until they finally lose all their funds, which sadly lots of players do.
My online casino safety rankings take all these factors into account. I cannot assure you that on any given day the rankings are entirely accurate but in the long run they will pan out, giving you a solid idea base of which casinos are safest over an extended period of time. What this means is that a casino ranked 5th in my ratings, might not actually be the fifth safest online casino, but it will surely be A SAFE ONLINE CASINO.