Of course not, I dont' recommend anyone go into a Church unless invited to share what you know as truth, otherwise your words will fall on deaf ears. Nor am I saying to go to the door and say come out, that is the Ruachs job, not mine. What I was saying is to prepare a place for those he would call out, give them a place to learn.
The only thing that can happen should you go into a church and tell them they got it all wrong is for them to kick you out on your "Judaizing keister", for that is how you will be perceived.
remember, there is a way which seems right for a man, and this means even those who think they are doing the work of the kingdom. Check out your Christian TV programs, they all believe that they are glorifying G-d with the things they do.
Regrading Paul: So you are equating todays churches with Paul's time and in the midst of all the idols of Athens?
He did not go in to them but rather was in an area speaking in his own corner and was overheard by the philosophers of the time and they asked him to speak with them on the "new teaching". It was an outside open echumentical area where anyone could have his say.
16 While Sha'ul was waiting for them in Athens,
his spirit within him was
disturbed at the sight of the city full of idols.
17 So he began holding discussions
in the synagogue with the Jews and the "God-fearers,"
and in the market square every day with the people who happened to be there. 18 Also a group of Epicurean and Stoic philosophers
started meeting with him. Some asked, "What is this babbler trying to say?" Others, because he proclaimed the Good News about Yeshua and the resurrection, said, "He sounds like a propagandist for foreign gods."
19 They took and brought him before the High Council, saying,
"May we know what this new teaching is that you are presenting?
20 Some of the things we are hearing from you strike us as strange, and we would like to know what they mean."
21 (All the Athenians and the foreigners living there used to spend their spare time talking or hearing about the latest intellectual fads.)
They asked him, he did not push in on their worship to tell them what they were doing wrong.
Paul was there not originally to preach, but awaiting Silas and Timothy, but the Spirit moved within him and he went to the synogogue first.
Here's a picture
http://www.bibleplaces.com/athens.htm