What rights, if any, does a material witness have?

due process right of the witness, who has not been charged with a crime, to not be unreasonably incarcerated. (Id. at p. 851, 89 Cal.Rptr.3d 264, 200 P.3d 879.) To have a material witness who has committed no crime taken into custody, for the sole purpose of ensuring the witness's appearance at a trial, is a measure so drastic that it should be used sparingly. (People v. Cogswell (2010) 48 Cal.4th 467, 477, 106 Cal.Rptr.3d 850, 227 P.3d 409.)