Anyone with experience using affiliate marketing for your store?

I'm currently setting up an affiliate program for my store, and the thought just crossed my mind: could an "affiliate" scam me by just placing some orders (or have friends place orders), collecting the commission, and then getting a refund/filing a chargeback? My thought was that this isn't really a common scenario, but is it something to watch out for? Or perhaps there are ways to prevent this from happening? Any feedback is greatly appreciated!