If I remember correctly, the network requests made in Qt are done in a separate thread. That's why you need to connect a slot for the network reply, whenever that returns. The problem with the Informed Individual plugin is that it currently does not give any user feedback before it receives a network reply, but it does not block the GUI, though.

In other words, there is no GUI-blockage when you hit the Informed Individual plugin. Just try to go back to scanning after pressing the plugin button.

On the other hand, making the clickAction() of a plugin into a threaded signal/slot system might be useful to avoid plugins locking up the whole application.