For short runs and/or slower speeds a flat ribbon cable may not pose issues on the bus. Having said that...
The CAN specification uses two wire twisted pair differential signaling. Since external interference tends to affect both wires together, and information is sent only by the difference between the wires, the technique improves resistance to electromagnetic noise compared with use of only one wire and an un-paired reference (ground).
Im not sure what Burnin has on the board in regards to can, but in addition to using a twisted pair, a terminating resister should be placed at each end of the daisy-chain of devices. Again, short runs may get away without issues. When you are using High-Speed CAN, a resister is placed at each end, bridging the wire pair. The resisters bleed off residual line voltage (aka reflections). The resister value is 120 ohms, which matches the cables nominal impedance of 120 ohms.
Low-Speed CAN is designed to have a resister at each node, which comes along with the hassle of calculating the values for the resisters.
/no I have never done extensive work with CAN busses in cars/
//go BMW, they switched over to Ethernet/IP, makes interfacing so much simpler//