(S (S (S (PP (IN In) (NP (BASENP (DT the) (NNS days)) (VP (VP (VBG leading) (PRT (RP up))) (PP (TO to) (BASENP (DT the) (NN rally)))))) (COMMA ,) (S (BASENP (NN police)) (VP (VBD had) (VP (VBN warned) (SBAR (IN that) (S (BASENP (DT the) (NN demonstration)) (VP (MD could) (VP (VP (VB attract) (NP (QP (ADVP (RB up) (TO to)) (NN 20,000)) (NNS people))) (CC and) (VP (VB turn) (PP (IN into) (BASENP (DT a) (JJ full) (NN scale) (NN riot)))))))))))) (COMMA ,) (S (ADVP (RB however)) (S (BASENP (DT these) (NNS fears)) (VP (VP (VBD were) (RB not)) (VP (VBN realized)))))) (PERIOD .))