Scenario 1:
Say there is a new kid in your class. You know that he drives an awesome sports car. You go up to him and say "Hey man, we should go out to lunch sometime-buy you should drive." Your only true motive is that you want to take a ride in his car
Scenario 2:
Same new kid with the same car but this time, you don't know that he has the car. You go up to him and say "Lets get lunch some time." You become friends and take a ride in his car
People shouldn't be used as a means to get to an end. The first scenario, in my opinion, is totally immoral. Ends don't justify means