Originally Posted by
KLouis
"Pure"
domestic flights (i.e. not the second leg of an A3 international flight) are
OA flights, code-shared with, and operated (sort of wet-leased, but let's not start talking about this matter again) by A3. Thus, the extra bag is only for M+B Gold members and not for the other *A ones. Dura lex, sed lex!

Thanks. Incredibly disappointing to hear/read.
It's unforunate their website contradicts this, which undoubtedly adds to the confusion.