This is such a silly question, is it not? This is not impossible though.
Affiliate marketing is a good means to attract probable customers. The more affiliates, the better conversion thus better sales. The affiliate will receive a commission in every successful referral. This is good for both the company and the affiliate, everybody happy!
I referred a friend to one of my affiliates. He was mid-way the sign-up process when he realized that his paypal account balance is less than what he is suppose to pay. He aborted the sign-up as he wanted to replenish his funds first before starting all over again.
This was the time the company has sent him an email offering 50% discount, which means that his paypal account balance will be sufficient. He clicked the offer and there it goes.
The company got its sales but the affiliate has nothing in his pocket..
What is your opinion, is is ethical? Is the company desperate enough to get a new customer at the expense of its affiliates? Well, its survival of the fittest. Whoever gives the best offer wins.
So next time you sign-up with an affiliate, check that the company your selling is not competing with you.