Invalid root Inport/Outport block connection

I don't understand the reasons behind all those rules described in https://de.mathworks.com/help/simulink/gui/invalid-root-inportoutport-block-connection.html, i.e. why these restrictions exist.

For example:

1) A root output port is connected directly or indirectly to more than one nonvirtual block port.

2) The signal driving the root output port is a test point.

Can any one explain those two?

Thanks a lot!