I remembered one of Paul David Washer's sermons said that some people were saved during a repeat after me evangelism. He mentioned the fact that these people were not saved because of it but in spite of it. Now why do some people get saved in spite of a "repeat after me" sinner's prayer. Now I do say that it can lead to a false assurance but there are times that preachers who use a sinner's prayer managed to lead people to true conversion because of other factors that were done right during the preaching.
The reason behind why some sinner's prayer evangelism results in true converts is because the preaching wasn't watered down in spite of the repeat after me sinner's prayer. I have noticed some preachers really explain the Law properly before the sinner's prayer is done. Some pastors have used Ray Comfort's approach in convicting the lost sinner into repentance of their sins. These people have genuine repentance then comes the people coming forward. After that, they have that deep sorrow that in spite of the repeat after me sinner's prayer being done, the person still had a genuine repentance of their sin and they genuinely believe the Gospel in spite of the presence of the repeat after me sinner's prayer evangelism.