One of the beauties of SwimRun is the LACK of rules. If you don't want to use paddles - no problem, if you don't want to tether to your partner - no problem. No worries about bike courses "open to traffic" or drafting rules. No worries about the course length, there are no set standards. No worries about comparing your times from another race. Its about getting from point A to point B through some amazing nature and sharing the experience.
As much as I think the sport is at its best when you do it with a partner there is certainly a movement to allow for solo entries.