The schematic net names are fully unique but if we have multiple pads
that are mapped to a NC pin, they need to have unique net names so that
they do not get connected to each other in the ratsnest. This breaks
the schematic parity check as we have modified the netname for some
pads. To work around this, we first maintain the zero-th net without
suffix and then add an additional check in DRC to ensure that we allow
unconnected nets as long as the share a common prefix with the schematic
netname.
Seth Hillbrand