We don’t need to theorise on these things because the rules laid down by the regulator are available for anyone to read. The only “prize pool” accumulation allowed in an online slot is a progressive jackpot.
Game results must be ‘acceptably random’. Acceptably random here means that it is possible to demonstrate to a high degree of confidence that the output of the RNG, game, lottery and virtual event outcomes are random through, for example, statistical
analysis using generally accepted tests and methods of analysis. Adaptive behaviour (ie a compensated game) is not permitted.
Game designs or features that may reasonably be expected to mislead the customer about the likelihood of particular results occurring are not permitted
Where the event requires a pre-determined layout (for example, hidden prizes on a map), the locations of the winning spots should not change during play, except as provided for in the rules of the game.