Some relevent documentation:
http://digital.ni.com/public.nsf/all...25795A000FC025
Essentially, it says that unless you have over 40 meters of cable there shouldn't be an issue (I'm assuming the highest bitrate to provide a lower bound), but also notes that the resistance of the resistor should be changed depending on the cable length.
However, the reality on an FRC bot might be different. I've seen people complain quite a bit about the lack of reliability from CAN on FRC bots and from Jaguars controlled via CAN. I didn't find anything with a quick search, but I expect there are threads from past years that could be useful.