It would strike me as very odd that the only people who seem to be sending their chips for slabbing all seem to be from the same geographic area (which is not a hotbed of chip collecting) as the slabbing company, yet somehow we are supposed to believe that there is no connection between these people.

Sure it is possible that the guy John met has no relationship with IGS other than as a customer of the slabbing service, but lots of things are possible that are improbable.