I use my UA CC to book most of my flights and have had status most years (but not every year) anyways. But I specifically remember a couple years ago when I didn't book using the UA CC and was told I'd have to pay bag fees.

But if someone posted an anecdote to the contrary, it wouldn't suprise me. Maybe one of those deals where it depends on who you're dealing with, kind of like fee or no fee for a small child accompanying you to enter UA Club on CC club pass.