With the introduction of Link cards, it makes a difference if some cards face you or face your opponent. Is there a rule that specifies that a card has to be played facing you?
Even it is not a rule per se the game is created with the orientation in mind, as most cardgames i know of, that your cards are readable for you. By turning the cards name to the bottom you would switch the game state as Link Arrows would point in different zones than intended.
While there is no rule in the rule book agaist it, there is a rule in the tournament floor rules (IV G. Game State)