Seller's agent gets earnest money deposit???

I'm in the process of listing a home for my aunt in Michigan and there is a clause on the contract that the seller's agent gets 50% of the earnest money deposit if the buyer backs out without cause.  I've never heard of that before (as a realtor from years ago nor anywhere that I've read currently).  Is that common practice anywhere... or just something that was slipped in.  

Chelsea