All creatures able to block enchanted creature do so.
10/4/2004 Lure does not give a creature the ability to block the Lured creature, it just forces those creatures which are already able to block the Lured creature to do so.
10/4/2004 If a Lured creature is in a band, only blockers able to block the Lured creature are affected by the Lure.
10/4/2004 The opponent does not have to activate any abilities in an attempt to make his or her creatures block. More specifically, a cost to block of zero mana is an optional cost you can choose not to pay.