Assignment Deals/Here we go again!!

Ok, I read the books, read the forums, and purchased the Success Academy and everything pretty much states that Assignment Contracts are legal. Well, when I spoke to my loan officer last night, he told me absolutely NOT. He said it is completely illegal and this is why banks won't fund these types of transactions. I decided to do some researching and spoke with 2 real estate attorneys, a realtor, title co., and loan originators who all told me it was not legal. How can this be? I was also told that you may find a title co. willing to work with you, but over time, you can get caught and go to jail. Yikes!! I wish I wasn't getting so many different answers. What is honestly true?