We should incorporate the results of issue #195 here. In short, we can't require this to be a cmi.interactions.n.id from the RTE as, in practice, nobody followed the requirements given there. Instead we should say that it is a string identifier, that it SHOULD (MUST?) lack whitespace, that it must be unique relative to other interactionComponents in the same array, and that it is the place intended to put values in use as cmi.interactions.n.id values.