Well it might not be called mesh by some rather fishnets.  In the old DC crossover "War of the Gods" one of the characters insists a strike team all be wearing their superhero costumes as symbols have strong power in the realm of magic and myth.  There is some aspect of truth to that, if you think about the ridiculous levels of nationalism that some countries have around something like a flag, then it is not surprising.  As a science student I don't believe that magic exists in the real world, though of course symbols do.  Is there power in symbols?  Show the Superman shield or the Batman logo to most people, whether comic fans or not and they will recongize it.  it stands to reason that if symbols are relevant to comic book heroes that the magicians have an ability to influence this particularly.  A lot of the magicians actually have very iconic appearances.  Doctor Fate is very much tied to the apperance of his (or her) helmet, which is of course the source of power, but other items are also there as well (medallion for instance).  With Zatanna the one defining item she wears and her one symbol could be considered her fishnets. Not as much of a symbol?  Well I have already been over the history of fishnets on a much earlier post but it is not really my point here.  Of course fishnets represent something else for a lot of different people, but using comic book logic about magic, Zatanna probably would be more powerful when wearing them.  In fact in the Zatanna miniseries that I recently re-read (the one that was part of the Seven Soldiers arc) she went into a major battle wearing a mostly fishnet body suit.  Of course it is not the source of her power, but in being iconic it surely helped.