Asking "What is no deposit bonus?" usually happens after a bonus has vanished, taking its winnings with it. The cause is almost always a condition in the terms: a deadline that passed, a withdrawal made too early, a cap on winnings or a clause about irregular play. Each of these can be seen in advance, and a short read of the terms shows which of them apply to a given offer.
Many bonuses limit how much can be withdrawn from winnings made with them, often as a multiple of the bonus or a fixed amount. Winnings over that limit are taken back at conversion, even after the full requirement has been met. The cap is easy to miss because it appears in the general terms instead of the offer page. On a small bonus it can make a large win on a volatile game worth only a fraction of its size.
Bonus terms include clauses on irregular play, and they are written broadly. Typical examples are betting on both sides of an even money bet, switching to low risk play to clear wagering, raising stakes sharply after a bonus is converted, or opening more than one account per person or household. A casino that finds such a pattern can void the bonus and its winnings. Reading the clause shows which patterns a casino names, and which ones it leaves to its own judgement.
Requesting a withdrawal while a bonus is active often cancels the bonus and everything won with it, and some casinos apply the rule even to cash deposited alongside it. A player can usually cancel a bonus on purpose from the account page, which frees the cash balance at the cost of the bonus. Knowing where that option sits, and what it removes, turns an accidental forfeit into a choice made with open eyes.
Typical examples include betting both sides of an even money bet, switching to low risk play to clear wagering, or sharply raising stakes after conversion.
Usually not. Opening more than one account per person or household is a common abuse clause, and it can void the bonus and its winnings.
A saved copy proves which version of the terms applied on the day the offer was taken, which matters if the casino later changes them.
Usually from the account page. Doing so frees the cash balance but removes the bonus and whatever was won with it.
Casinos can revise their terms, though most promise that a bonus already claimed stays under the version the player accepted at that time.