When they ask if you want to share what you type or say with them, in order to improve the experience and for you to get more relevant suggestions or more accurate spell checking or whatever, they only focus on the positives.
But that's not enough. I want them to say that your delicate and private conversations might leak and be used for nefarious purposes by disgruntled employees, state agencies, hackers or future owners of that data, because that's the truth.
Much like how cigarettes packs have graphical warnings on them. I'd like that very much, because as an ex-smoker I can tell you that those work. But of course, it would hurt their business to admit it, so they'll never do it willfully.