Such requirements could arise either as a result of voluntary agreements among retailers and apparel suppliers or be mandated through regulation.
( ( Such requirements ) ( ( could ( ( ( ( arise either ) ( as ( ( a result ) ( of ( ( voluntary agreements ) ( among ( retailers ( and ( apparel suppliers ) ) ) ) ) ) ) ) ) or ) ( be ( mandated ( through regulation ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Such) (NNS requirements)) (VP (MD could) (VP (VP (VB arise) (ADVP (RB either)) (PP (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (NP (JJ voluntary) (NNS agreements)) (PP (IN among) (NP (NNS retailers) (CC and) (NN apparel) (NNS suppliers)))))))) (CC or) (VP (VB be) (VP (VBN mandated) (PP (IN through) (NP (NN regulation))))))) (. .)))
Mandates and regulation could not help to set requirements, as no one actually listens to regulations. 
( ( ( Mandates and ) regulation ) ( ( ( could not ) ( ( ( help ( to ( set requirements ) ) ) , ) ( as ( ( no one ) ( actually ( listens ( to regulations ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Mandates) (CC and) (NN regulation)) (VP (MD could) (RB not) (VP (VB help) (S (VP (TO to) (VP (VB set) (NP (NNS requirements))))) (, ,) (SBAR (IN as) (S (NP (DT no) (NN one)) (ADVP (RB actually)) (VP (VBZ listens) (PP (TO to) (NP (NNS regulations)))))))) (. .)))