$8.88 max bet sounds like one of those Asian themed games like 88 Fortunes with the pot that fills up with coins as you get wilds, then when it "gets full" closes and you get to pick to match 3 for one of the progressives.
If you read the rules, getting a progressive pick is random and has nothing to do with how full the pot is.
But that doesn't stop people from thinking it's due.
I've seen some extreme crazy behavior around these when those pots are full, so they probably made that sign to avoid incidents.