Rtn1, my Sunfire poweramp has 2-prong connector and everytime I try to touch any of my equipment pieces I grab a great piece of the static charge especially during the dry seasons or winter when heater is always on. So figure to have the same with cheater plugs.
As long as at least one of the interconnected components has its safety ground connected, the chassis of all of the components will be at ground potential. So the static discharge you feel would be due to the static voltage on your own body discharging to ground (static buildup being at its worst in dry wintertime conditions, and especially if you have been walking on carpeted surfaces). The same thing would happen whether or not cheater plugs were used on some components, as long as at least one component has a 3-prong plug which is not defeated.
If no components have 3-prong plugs, or if the safety ground is defeated on all components (which are situations that should be avoided, as I indicated above), then the chassis can "float" to substantial voltages which could cause a shock (typically a mild one).
Regards,
-- Al