The sidecar has reverse voltage protection, so you should be OK if you "accidentally" hook it up backwards.
We blew a sidecar once because we had an excess PWM cable hang down and touch the negative post of our PDB, causing a short. Anything is possible, though I don't see how a short in the ribbon cable would blow something in the sidecar. Everything in the sidecar is "downstream" of the ribbon cable, and shorting the solenoid breakout to one of the 4 grounds in the ribbon cable would be more likely to blow the solenoid breakout than the sidecar.
Here are the control system schematics to help diagnose what's happening:
http://www.usfirst.org/roboticsprogr...stem-resources