Discrepancies exist in the literature about the interpretation of acoustic emission (AE) experiments with technical superconductors. At least three different origins of AE in short sample experiments have been identified: (1) shear transformation during mechanical strain, (2) friction by wire motion, and (3) flux motion during current or field sweep. This last origin, however, has been disputed recently. The paper discusses the published results and shows that flux motion is clearly an origin of AE. Further data are also presented to support this conclusion.