Oh come on, that joke is sooo old now, why does artists keep doing it with all new girls (Doesn't Littorio have a single ponytail?) ? Don't they have a little more imagination ?
Her official artist, Jiji, has, if you look through his works, quite a thing for Mami (and apparently, paizuri with Mami or shipping MadokaXMami)... Hence, I doubt this is a coincidence...