Quoted from HighVoltage:More ST Premium coming? Interesting.
Are you keeping track of the ghosting rate? Any policy on that?
If you're concerned about insert ghosting I suggest you wait until the reports of it occurring stop. Then buy. don't see how or why a distributor can or should have a policy on it outside of keep and eye on it and see if it gets worse to the point that your inserts are chipping and wearing causing playfield damage.
I for one have a game with ghosting on the inserts, but after the initial ghosting, it has not gotten any worse. That was over 1,000 plays ago.