We have to remove this, because it brakes the "Reading default widget config from the connections" function.  
For me it is a good idea to have the default behaviour of a widget on the no button connection and connect secondary widget functions only if explicit requested. IMHO this will not make skinning harder. Also I can see some other drawbacks and limitations in current and future mappings if we emit via all connections by default.

* Reading default config from connections will not work reliable. Because the widgets like WPushbutton behaves by default different if you connect Left, Right or No-button connection 

* If we implement e.g. a special function on a left button connection, the default widget function will still emit via the left connection and my produce undesired or concurrent value changes

* If we allow now a IMHO wrong e.g. right connection on a widget that currently only has support one default connection and it is working well, we have to deal with those skins if we later add e right button function to the widget. We cant rely on that it is not connected in legacy skins because it was working.