>This is a common trick utilized in poker, where good players will apply a certain playing style, while placing smaller bets, let their opponent adjust to your style and then suddenly change to a more aggressive style.
Pardon my ignorance of poker, but won't the opponent notice that you have suddenly raised the stake and that something could be afoot?
Playing aggressively in poker usually means betting more than your hand would otherwise dictate - but your opponent doesn't know what your hand is.
So - you play for 4-5 hours, folding on weak hands, and always raising on strong hands, and then, once people think you are a grinder, you start betting on weak hands; other players fold because they were used to you betting high stakes only on strong hands, you take their money.
To clarify for the poster who asked you the question, playing aggressively might mean better more than your hand otherwise dictates, but it might also mean betting more often even if you don't change your bet size.
For example, you might always fold low pairs 22-66 initially (and perhaps conspicuously reveal that you folded them) but then start raising with them later. If your opponents were paying attention, then (a) they will think you have a good hand, and may be scared into folding right now, but (b) even if they don't, they won't suspect you of having a low pair, so that if e.g. a 2-6 comes up on the board and gives you three of a kind, you have an advantage because your opponents won't consider that you have this hand.
In my opinion, the parent example was rather oversimplified. If a player started playing more aggressively, that would be an obvious 'tell'. Most opponents would recognise that they should play more conservatively until they figure out what's going on.
However, this strategy really just needs one sucker: if it works, it works.
Pardon my ignorance of poker, but won't the opponent notice that you have suddenly raised the stake and that something could be afoot?