A tag used when there is absolutely NO violence, threat of violence, or interpretation of violence in the image.
If there is no violence in the image, but it has one of the above factors in it, use the non_violent tag instead.
If the only broken requirement is the last one (NSFW content), use vanilla instead.
In order to maintain the civility of this board, do NOT post any comments that could be considered as 'violent' or 'abuse-oriented' on these images. Ignoring that rule can potentially result in a BANNING.
In shorter terms (and straight from the admins mouth): Family_friendly is exactly what it means. Something you can show to your mother or daughter, or your friendly local ultra-conservative neighbor without the nagging question of "should they see this?"
This tag implicates non_violent (learn more).