Anyone with a "system" for roulette will be welcomed into any casino in the land with open arms and a free drink.
that should tell you something
there are two systems for roulette that can make you money, both of which have got people barred from casinos. they only work on real roulette tables though
the first is a perfectly legal method. i'm pretty sure that it requires a roulette table with a 'drop zone,' but it might work without one
a drop zone is a roulette table which has a specific area where the roulette ball almost always falls towards the centre. this can be caused by the table being slightly off level, even by just a few degrees.
once you have found a table with a drop zone you will need to sit at the table for thousands of spins, recording the number that comes up each time. with a properly set up table you wouldnt find any number coming up significantly more than any other number, but if the table has a drop zone then a few numbers will come up more than others. obviously you spilt your bet between the numbers with higher probability and, over time, you will make money
the second method is only legal if you do it without any electronic equipment to help you, which is what derren brown tried to do and almost managed it, but its almost impossible. it also requires a table where you can place your bets after the ball has been released.
by recording the speed of the ball and the speed of the spinner, you can determine roughly where the ball will land. it wont give you a precise number, but it will give you an area where the ball will land, which is enough to put the odds in your favour