Ive seen alot of weird patch wires with PCBs over the years. Gross oversight by the engineers or some sort of schematic/PCB error. 

Luckily these days, that dont happen often at all. Considering with most CAD packages, the PCB is linked to the Schematic. As long as your Schematic is OK, you cant really fuck up the PCB unless you overlap traces, but the DRC will alert you.