It is tacky just to ask if it is tacky.
To me I see this issue as a grey area, I would never ask if I was traveling only in discount Y. And I am not PA kettle thinking the amenities of F and J are a God given right when you purchase bottom basement Y. I on the other hand travel most of the time in J and have seen the AC dozens of times and would like to see the FL once. I do not have quite enough miles for an F ticket, and will probably never have the money to make F a "reasonable" purchase.