RP is as sandbox as you can get in an MMO. I see absolutely no reason to leave 100% of your RP with someone up to chance. I've touched base with players countless times over many different games over the years to see if they wanted to do a scene. The advantage you have in doing that is that you both have at least an inkling of an idea as to what your RP will be moving toward. All in all, I agree with what the others before me have said. There's no harm in setting up RP with someone or with just letting things happen randomly.
