That is unfortunate. Perhaps a better use of time would be to file a bug against those cycle routing applications to change their default assumptions and only use highway=footway ways if they are explicitly tagged as bicycle=yes/designated/permissive? Having that as a default would surely cause fewer routing errors from avoiding using pavements which actually *do* allow cycling (false negatives) than there are currently routing errors from suggesting using pavements which don’t allow cycling (false positives).