umm yea, but the bike isn't made of just a ball of CNT's. They are impregnated into the epoxy to add strength to the matrix (think of the CFRP with CNT's as a composite inside a composite) They aren't getting loose any time soon. The only person that has to worry about the toxicity is the person loading up the machine that mixes the CNT's into the epoxy.
Studies have shown that the human skin is actually a great blocker of CNT's except at the folds in the skins (like the back of elbows and knees.)