In your studies to get your 107 certificate, I think you will find that everything is not as black and white as everyone would lead you to believe. There are huge gray areas in the current regulation system. Currently, anyone can fly as a hobbyist, as long as they have no
true intent, at the time of the flight, of anything other than recreation, and later sell those images and video to their heart's content! Many mistakenly believe that they cannot ever sell any drone images or video taken recreationally, unless they had a 107 at the time, or unless they first obtain a 107 before they sell them. They can! Establishing your true intent
at the time of the flight is the crux of the issue. The burden of proof is not on you, if you state it is strictly recreational. The burden is on the FAA to establish by the totality of
all the circumstances (before, during, and after the flight) that your true intent at the time of the flight was actually commercial and not recreational for there to be a problem. If they can meet that burden, then your recreational claim is no longer credible. Just be totally honest with yourself beforehand, and then let your conscience be your guide, and enjoy your recreational flight!