IMHO it is a bit strange. I can call to a method which is asynchronous and I expect that it does something. If I pass a callback as parameter I expect that when it ends, my callback will be performed. If there is not defined a callback, I won't know when it finishes but the method should run in the same way. This is my point of view, although I could be wrong as usual jeje, what do you think @jmcanterafonseca ?