The camel-restlet component populates Camel Exchange from Restlet Response via DefaultRestletBinding. However, it only properly reads binary contents if media type is "application/octet-stream". In all other cases it reads contents as String, even if contents are binary. For example, if the contents are of type "audio/wave" - a normal .wav file returned by a REST service - they would be read as a String, which results in an unplayable file.
See code extract: