When triggering a custom event on an object which has a property with the same name, you get an error:

TypeError: Property 'custom' of object #<Document> is not a function

document.custom = 1;
$(document).trigger('custom');

This makes it impossible to use custom events with property names on non-DOM-objects when there is a property with the same name:

var obj = {name: 'John Doe'};
$(obj).trigger('name');