I agree with your Flyboys reference and point, that THOSE commercial models are indeed commercial.

However,
lets examine the automotive television advertizement
that had a model plane hit its panel to demonstrate the panels dent resistance.
Someone was piloting that RC plane for the purpose of getting filmed, and that filming was Commercial in respect to selling cars. So I believe we agree that the RC plane flying was not hobby.

But you ask that some line be envisioned
separating that example of a pilot demonstrating for sales (a likely compensated pilot)
from other pilots compensated for demoing for sales.

Because "film" got used the CA film guys invited themselves to make a decree,
and they didnt side with the RC plane pilots


If Clem&Cletus want to sell DVDs of their L337 Ski11z at hovering,
so they film themselves at the club to be sold as DVDs on Ebay,
is that a commercial activity? CA film guys appear to say it is.
If they want to sell their special 22x2w Silk props by filming an ad of a UAV (98"yak model) demoing the prop hovering... how is that different than selling cars with a UAV demoing hitting the car