The accelerated move order for the Sicilian Dragon is supposed to prevent white from playing a typical "Yugoslav" type attack with queenside castling and a kingside pawn storm. This doesn't mean white won't sometimes try it! As a player of the accelerated dragon, you know you're supposed to punish this 'mistake', but in the practical case, it's not always easy.
Here's an example from one of my recent correspondence games where black cracks the challenge. The game shown is how it played, but black actually misses a tactical knockout during the attack, check the move list.