Most of time it isn't about lying, its about small print hidden in the document.

Legal text is often opaque to laymen because it has specific legal meaning, plain commonly understood language doesn't have specific meanings so you get into situations where even the lawyers aren't sure how it should be interpreted.

To use a tech analogy, the lawyerese is the source code, if you want the ultimate truth, go there, you should be pairing it with adequate documentation though.