I prefer to be honest about as what a person is "selling" to another. For instance, "Wouldn't you want to.....?" These actions of "selling" are, in a sense, manipulative. Manipulation is, at it's best, the ability to create a desire for an experience. The ultimate value of the experience is, of course, determined by the user.
Of course, permission is implied, as in the teacher/student relationship or in the forms of the assault of advertising. People understand that others have to make a living, so they listen to their "pitch" about the
value of what is being sold. People in business attempt to create a "NEED" for their services. Students buy courses orchestrated by teachers.
In our culture, the more someone must pay for an experience, the more they tend to value it. In some forms of manipulation, permission is disregarded to the point of coersion. There's a fine line between implied permission and coersion.
For me - when this permission gets violated, it really upsets me. Makes me wonder when or how I agreed to it so I can use whatever power I have to retract that permission.