I don't think Mab can create the battleground on her own. I think it really needs her and Titania both gearing up for battle to create it.
Remember - it's not the Table that's the conjunction in this case, but the Battleground around it.
(The table might also be a conjunction of a sorts, but I think it would have been a really, really bad idea to kill Maeve on it - might actually spread the contagion rather than remove it...)
