Actually while this case is somewhat vague, the symbol is used as a sticker. Say a parent goes for ice cream. The kid is given a cone with a cute sticker on the napkin. This signals an abducter that that child is maybe with a single mom or whatever. It marks the child for abduction or worse.
Its good to know this and have no issue with attention being drawn to it.
That signals an abductor that he is about to get the chance to explain to his maker just what in the he11 he was doing.