That's a very narrow take on the matter. One can be deceitful with perfect information. In general you can use small prints or psychological tricks and conceal

That's a very narrow take on the matter. One can be deceitful with perfect information. In general you can use small prints or psychological tricks and conceal your true aim. If you know that by presenting information in a certain manner leads the user to be more willing to accept harmful conditions, then you're being sneaky even though you're technically being open.