I've had similar situations, ghost, where on a nuisance trip call, I'll ask (if it isnt terribly inconvenient) to plug the appliance into a different gfci circuit for comparative reference. if the other gfci trips within a similar time frame, the owner now has a demonstration that its the appliance; though the brand new issue may thicken their heads still.
even so, a different gfci "holding" the redirected appliance indicates almost nothing, possibly a gfci that has had the trip thresh-hold rise, or the other gfci is no good. (the p&s guy had also said that their gfcis don't degrade in amp sensitivity, but on failing - the ruined kind - won't reset.)

incedentally the P&S guy DID say that changing to class B protection would defeat the personnel protection purpose.

I just re-read your post - duh, you DID do the try it on another gfci. it's the "it cant be a counterfeit UL logo, it's brand new, your wiring caused it to melt" thing

Last edited by Samurai; 08/20/07 11:47 AM. Reason: p.s.