Thank you for some excellent comments. As Timothy pointed out, there is nothing Biblically wrong with street preaching and evangelism. That was certainly not my point. But I think you readers got that. It does however lead to a good opening to answer Timothy's question about the deception part.
Given that a believer is gifted and empowered by the Holy Spirit to evangelize, street preaching is a wonderful way to do that as shown by the examples of Jesus, Paul, John, Peter. etc.. However, not all are gifted in this way. That's where part one of the deception comes in.
How many Christians are taught to believe that we must all go out and evangelize the world by public speaking? And how many of that group are scared to death to do that? How many of you still feel that way even after going to the EE class? Well, there's a good reason for that.
First, it's not your calling (hold your comments for just a second folks! Yes, everybody is called to witness AND make disciples. The critical issue surrounds how we do that as a Body.) Second, it's not your gift. There are folks in the Body who are gifted as evangelists. Check out I Corinthians 12-14, Romans 12, and Ephesians 4 for the rest of the list.
Each person, as they are uniquely gifted by the Holy Spirit, fulfills the Great Commission. For instance, those with the gift of hospitality evangelize, witness, and make disciples most supernaturally in the home as they serve and make folks feel at home (or whatever else folks with this gift do! :-) My gift is prophecy so I witness and make disciples in a very direct way through sharing God's Word boldly in print and small group settings.
The calling is the second area of issue. God first gifts His Body, then He calls each member uniquely. Have you made both your calling and election sure? Do you know that it (your calling) can change from time to time as the Spirit wills? Perhaps you are a gifted evangelist but NOT called to street preaching. You can only know with certainty the words of truth by seeking them directly from heaven. Follow the path from Romans 11:36 through 12:2.