They have all kinds of training for missionaries...
Professor Robert Millet teaching at the Mission Prep Club in 2004 http://newsnet.byu.edu/video/18773/ <-- Complete and uneditted
Timeline... Subject...
0:59 "Anti-Mormons..."
1:16 "ATTACK the faith you have..."
2:02 "We really aren't obligated to answer everyone's questions..."
3:57 "You already know MORE about God and Christ and the plan of salvation than any who would ATTACK you."