Never had the brake wires damaged during transit.
Though I do have first-hand experience with poor factory installation.
Because I screwed up and burned out a set of wheel bearings and damaged the drum and shoes, I decided to replace and update the whole axle, brakes and tires.
During disassembly I found the wires that ran through the OEM axle tube were pinched under one of the U-bolts holding the axle to the leaf springs. The brakes never worked properly because both sides were shorted to ground for 25+ years!
Along with the new axle, I got 50% larger brakes and properly functioning electrics! Having the trailer brakes handing most of the mass back there is a wonderful thing.
So, yes, the factory can screw up badly. Routing the wires clear of the moving parts is always a good idea.
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!