Hilariously, that does work for a while. The more unused credit you have, the better your credit. You would think having a half dozen credit cards hurts your credit, but nope. It's the opposite.

Opening them will hurt your credit for a short while, but moving debt from 0% interest card to 0% interest card occasionally will increase your credit. Leaving the old cards open and empty will only make youre credit rating go up. You do not, at all, have to use them to maintain them or increase your credit score.

Eventually you will have to pay, and it's entirely likely to be the worst time for you as passing the buck with debt tends to lead to building more debt, but it's possible. Credit is addictive, so they want you to have more of it.