I think there's a big difference between "fitting" and "being able to get into it". When something fits you, it looks right and feels comfortable. Squeezing oneself into a smaller size and looking and feeling like a badly made sausage doesn't count as far as I'm concerned, neither does not being able to fasten something - Yes, we do often walk around with our coats and jackets undone, but we do need to be able to fasten them comfortably when necessary. It annoys me when these buggers try and persuade us that this doesn't matter, and like you say, those who do follow this dodgy advice will probably hang onto something they've regretted buying, because it's less hassle/cheaper to bung it in the back of the wardrobe and promise to slim down into it than it is to return it - and they bliddy know that! It's so unprofessional. "Tailoring" is another word they like to bandy around quite a lot, which is not a term that should be used to describe mass produced polyester tat from the far east - It also conjures up an image of bespoke items, made to measure and that every last stitch should sit in the right place, the fit is of pinpoint accuracy. To say "The tailoring that has gone into this garment is incredible, but don't worry if your size is no longer available, go up or down a size" is frankly ridiculous!
How is this possible Gok? It isn't - If this jacket fits everybody, then why make it in different sizes?!