An event that raises itself - is it too complicated?

Question

I have a little problem. I'm writing a resource loading and caching system, in which user can request a resource, and set a callback to be called when resource is loaded (and/or wait for load to finish). This leads to code like this:

var waitobj=Loader.RequestObject("foo");
waitobj.LoadFinished+=delegate{ Bar(); };

However, since resources are cached, the call to RequestObject may actually complete synchronously. This means that when callback is set, request is already finished, and callback is never called. I thought up a clever trick: let's just check the state of request in the event adder itself!

public event LoadFinishedHandler LoadFinished {
    add {
        if(Finished)
            value();
        else
            m_LoadFinished+=value;
    }
}

This will call the callback function no matter what.. but my coworkers said that this method is too complicated and no one will be able to maintain this code. I like this trick anyway, but I'm obviously biased.

What do you think, is this trick too clever for its own good?