If I understand correctly, when there is no winner the prize is rolled over the next day. The technique involves playing these days specifically, and getting a

If I understand correctly, when there is no winner the prize is rolled over the next day. The technique involves playing these days specifically, and getting a big enough coverage of the numbers. That means that if the (global) prize becomes big enough, then for this day the lottery gives out more money that it cashed, but it's actually money they accumulated during the days there was no grand prize winner. So in average the lottery doesn't lose money.