I routinely perform QA checks on ECW and GeoTIff files. When I use transformers like CoordinateSystemExtractor, it seems that FME gets confused by the presence of the sidecar files (.ers and .tab). I can check these via another work bench, text file reader, or a string transformer. But right now, to check only the ECW or GeoTiff files, I first have to move or delete thousands of side car files; these are often found in multiple directories, so this can take a long time.
I think it would be a good idea for FME to include the option to ignore the sidecar files, either in the ECW/GeoTiff reader, or within the transformer settings.