i have heard there are two reasons why there are no crosses on the mormon church.
one idea is that the cross is symbolic icon of adultery.
yet, temples have statues of the angel moroni.
there are huge amounts of symbology in the temple.
God has said that he hates it when people speak in signs. and jesus said it is an adulterous generation that seeks after signs.
however, signs will follow those that believe.
then again, it says in the book of revelation, the devil will come with signs and wonder, even fire coming down from heaven.
many protestants agree that statues of catholic saints is either direct idolatry or not allowed in scripture. the bible says we shouldnt worship the queen of heaven, even if it was a cultic sect in ancient israel, it still holds some paralel commandment today, and yet many people actuall worship Mary. this by itself is a form of idolatry.
so, yes, in most public worship, there are not idols and symbols that would represent some idolatry or apostacy. then again, the lord commanded moses to lift up the brazen statue of the serpent. the reason are found in the scripture that justify it.