Rules against multiple accounts from the same IP or the same address accepting a bonus offer are virtually standard in the industry.
Just the chance that a dynamic IP I might use could overlap with another trader one of the reasons that I recommend staying out of the whole bonus game.
Deposit your own money. Trade your own money. Withdraw your own profits. Then, if a problem occurs, it's a thousand times easier to see where the problem lies.
But for a broker like FBS who makes their own rules and decisions WITHOUT any regulatory power over them, even if 'Deposit your own money. Trade your own money. Withdraw your own profits.' and then a problem occors if wouldn't be any easy to resolve - as FBS makes their own intepration on Terms & Conditions and never has to follow it if they don't want to - all they need to do is to finds all kinds of cheap excuses for 'why the terms & conditions don't apply to us here' while 'the traders have to follow the T&C strictly no matter how'!