Official FAA position on 'Furtherance of business'?

Hello. Just reviewing the new 'Sport Pilot' regs for their
implications to me as a CFI. Looks like in 61.315(c), the FAA has kept
the unfortunate limitation on being PIC of an aircraft 'in furtherance
of a business' that they had on Recreational Pilots.

Does anyone know of any 'official' FAA definition of this term? I
looked in FAR 1.1, and couldn't find anything specific. I've talked
with other CFIs about this and (surprise) there seems to be a
difference of opinions about this. I think CFIs are like
economists...put two CFIs in a room together and you end up with three
contradictory opinions.

My interpretation of this means that the flight itself may not be for
the specific purpose of furthering a business, but that an
'incidental' activity at the destination related to the business is
legal. For instance, I'm a sport pilot and fly to a destination to see
a friend of mine who I also do business with. We play golf (the
primary reason for the trip), but 'talk' some business during the golf
match. The *purpose* of the trip was to play social golf with a
friend, but the fact that we are playing golf and talking business may
further my business. I can't imagine the FAA expects me to tell my
partner "We can talk about anything else, but since I flew here, we
can't talk about business."

One CFI I talked to said basically that he thinks that the FAA expects
*precisely* that. The that limitation precludes the exercise of the
certificate for *any* flight where there is a reasonable expectation
that business may be furthered as any result of that flight.

I know this seems like splitting hairs, but many people have had
'interesting' experiences with the FAA because of misunderstandings or
differences of opinions like this.

So...doees anyone know of any enforcement actions or letters of
interpretation where the FAA directly and specifically commented on
this issue?

Cheers,

Cap