Hard to fathom 16 pages about crop or no crop. All kinds of theories. There is only one sure thing: one gets in the darkroom (or to monitor) checks out the whole frame and if original idea is clearly not the one anymore, here comes a crop. Trying to stick with "no crop at any cost" is not creating anything, there is a different word for it (take a pick), but it can be argued that that is the actual taboo.
I can't imagine a vast majority taking all kinds of aspect ratios/cameras into a field and think of which one to use before a scene is shot. Composing for aspect? Yes, all the time, in a sense that whatever appears important is fit into the aspect camera is set up for, and ... see you later as to what stays afterwards. It's not about being careless with framing, but it isn't about splitting an already split hair ether. It's like trying to see if there is a rounder circle.
Typically, whatever camera is out there, it shows what it does, a scene is framed within those confines and gets later re-examined and if needed, cropped into a new shape.
But I am curious, given some responses, how much some appear to mull over the theory behind crop/no-crop, how many go out and take NO photograph in the end, due to whatever did not seem to fit whichever? Perhaps go back home, pick up another piece of gear and go back to try again?