Distinction without a difference? If the weighting is sufficiently extreme, it becomes functionally equivalent to gaffing.
Good example.
The regs include a few general safeguards such as the 75% minimum payout. Here's one from technical standard 2:
Generally though, designers are allowed to be very, very tricky. I'm looking at it from the perspective of accurate analysis. Some of these new games are very difficult. For a highly competent slot AP, this may be a good thing because it discourages competition.