And there is one thing we can do in our side to avoid this to happen, and that's to change the user seed on each bet. But this solution is a complex task for the user if he want to place a big amount of bets. Maybe a betting bot can do this magic.
It isn't complex at all. There's a checkbox on the multiply BTC page to randomise the client seed on every roll or if you are playing manually you can simply reload the page.
And for the hi-lo game what you say can't work because the house can't know if you will choose HI or LO at your next roll.
Am not sure about this! Some gamblers follow predictable patterns when placing bets or use well known strategies (martingale). Am not saying freebitcoin.in are doing this, but analysing the user's gameplay may give the casino an idea on what's the player's next bet is going to be.
What I don't get is why they need to change the server seed for each new bet! Given the reputation of freebitcoin.in, am sure there is a good reason for this.
The number of players is huge on Freebitco.in, it's way above most of casinos, so I think it would need a big amount of computing resources to assign a specific server seed to each player and letting them changing it whenever they want. Moreover if a player manages to guess his server seed by chance, he will be able to win all his rolls until the next server seed rotation.
You are spot on with the point that we don't know if you are going to bet hi or lo. We also don't know if you are going to change the client seed or not. Both of those things mean that if we tried to anticipate then someone would work out when we would do it and they'd be guaranteed to win.
Some small sites use a static server seed but you're right that it would be impossible on a site this large. The "computing resources" more specifically disk space required would be astronomical and make the site financially unviable. Most people won't even know what it is and will never reveal their server seed at all meaning would have to store all their rolls for eternity. With over 135 billion rolls so far that would be infeasible.
It's also completely pointless. Both systems perform the function of being provable fair meaning that every player has the opportunity to prove if we cheated or not to themselves. Changing the system just because a handful of customers have a preference isn't a good idea.
I observe something similar in other online casinos, especially where there is a free spin of the wheel of fortune, as soon as you started spinning, the server already knows what you got and even before the end of the spin, this conditional win is credited to your account, at first I thought it was all about a big ping, but it turned out that it was not so.
The server knows the result as soon as it receives your client seed and bet details. On most sites, there's some sort of animation going on to keep you amused while you wait for that information to come back over the internet to you.