When Batman cut Robin free from his bonds by using the Batknife, he made amazingly short work of the job - especially considering the fact that he was holding the knife upside down and "cutting" the rope with the blunt edge!
When Batman was tied up under coffee pot and it dripped "acid" there were wet spots on his chest.
Catwoman has Eau De Chat perfume on. It is a poisonous perfume and Batman should be dead. Batman has Batplugs up his nose to protect himself. However, Catwoman's henchman do not have Batplugs. Therefore they also should suffer harmful effects from the perfume yet they do not. They are unharmed without any explanation.