Both signs were clearly visible to the woman from the angle before she approached the Guard and horse. Since the introduction of the pictorial sign touching the horse has greatly reduced but no matter the position of the signs or how many there are some people just think the rules do not and/or should not apply them.
As usual, the guard allowed them to break the rule. Pretty much all of the Blues ignore the rules and allow tourists to touch the horses! The mother is also teaching her daughter to break rules and to do what she wants!! Bad form from the guard and the mother.