For example if we have custom object:

var obj =
{
  init: function() {}
};

and we trigger custom event on that object:

$(obj).trigger('init');

object's "init" function gets called automatically.

Test fiddle: http://jsfiddle.net/pSAzu/

In this test example we get stack overflow exception which is very hard to spot. Because of that I think that no object method should be called automatically when triggering event.