@ Don
With all due respect I would ask that you supply information that proves this hypothesis in detail and trust me Don; I am not being a wise-A88 when I say this. The GFP provides a needed function and assists in a glowing arc condition more than the standard AFCI circuitry which is looking for a characteristic during the waveform half-cycles of the various arcing pattern would but those conditions are only a sampling of given issues. Of the major producers of GFCI products, one major maker no longer includes GFP in their circuit breakers and they still pass all compliance tests in UL1699. The adding of GFP by some manufacturers is to simply pass the end line cotton test (UL1699) more effectively but it is not the only way to achieve this product compliance.
I do believe GFP in all circuit breakers and Branch receptacle type AFCI's bring an added bonus over standard OCPD's but we have to understand the service they provide and the intent of the product. Those "very few more faults" just may be what saves a home and occupant. The problem is we can't quantify this in numbers but we do see a decrease In home fires since the advent of AFCI devices (as stated in the 2012 NFPA Publication on House Fires). Remember that Smoke Alarms just warn us...AFCI's can potentially protect us and our homes when installed....only when installed.
Now I will agree in some rare cases ( and they are rare but all things rare become fuel for a fight) we see issues with AFCI Devices but considering the millions that are sold each year the percentages are so small that it is not a concern I hold high on my agenda of debate topics. It always amazes me that (not you, just saying) when electricians have a problem with an AFCI they choose to voice opposition to them without taking responsibility for letting those who can fix the problem know....why not visit
www.afcisafety.org and post the nature of the problem, location of the problem, what has been done to try and resolve it and contact information on this website and it will help to resolve all of the problems in the future...its like the NEC, unless we get involved we really are just crying wolf to the problem.
Ok....I'm done with that rant......