In reference to Mr B’s rather unusual definition of rigged, my position was that you imagine a bet on the outcome of a (fair and entirely random) roll of a dice, where numbers 1-4 pay nothing, 5 is money back and 6 is 2.5 times your bet back.
That game can in no way be accused of being rigged under any sensible definition, yet it is a profit yielding game for the vendor with a mere 58% long term RTP. It is also exactly how online slots work, just a much more simplified example, equivalent to a single reel, single win line slot.