Through dumping the ROMs and emulating the machines, it was found that the machines were effectively forcing losses at certain points in gameplay; from the same memory state, you bet high and the machine goes low, or you bet low and the machine goes high, giving you zero chance of winning.
There was a campaign called Fairplay that I believe resulted in a fairly small print label being placed on the machines stating that they would at times give no chance of winning; not a great win, but at least it was being said somewhere - http://worldofstuart.excellentcontent.com/fairplay/fruit/bre...
The FairPlay site by Stuart Campbell is actually still up, although I remember first reading about it back in PC Zone personally. There's details on there about replicating the findings, but unfortunately the links are broken; http://www.worldofstuart.excellentcontent.com/fairplay/fruit...