That in itself will not violate her probation. However, as I am sure that her license got suspended due to missing the hearing, if she drives she is exposing herself to picking up a driving while license suspended charge. She should get this cleared up asap.
Any violation of law or of the conditions of probation could subject the probationer to a motion to revoke. However, this is a minor infraction; get an attorney ASAP to re-docket the case, set aside any bench warrant and resolve the matter. Time is not her friend.
I am trying to give you a general answer to your question. We do not have an attorney-client relationship by this response on the avvo website. I have not been retained to represent you. I am licensed to practice law in Kentucky and in federal court in this state and the Southern District of Indiana. You need to seek legal advice from an attorney licensed to practice in your area..