Buyers, chose your lender with care

I am not sure if very many agents have had this happen but today, it happened to me.  A potential buyer last week seemed very interested in using me as their buyers agent.  We spoke, sent texts and emailed back and forth.  Today I called to follow up and was informed, “oh sorry but I found another real estate agent through my bank”.  Uh oh...with a sinking feeling in my stomach I ask, “is it through USAA ?” to which he replied “yes it is”.  Here in Fayetteville, NC this seems to be an issue that comes up time after time...we have a huge amount of military who use USAA to bank (which I also use to do my banking).  However, when people go to use them for a mortgage they are offered up to $1500 cash back if they use USAA  as their mortgage lender. 
This is very frustrating to me as an agent.  The buyers have no idea they are paying for this $1500 they are getting back in fee’s and sometimes higher interest rates!  They are also getting the next agent on the list...not always the best agent for them, as well as an agent that is giving up a huge portion of their commission just to get the business...which again is not always to the clients best interest.  I have heard of agents only showing houses with bonuses or higher commissions just so they can make more money.  
I personally have had two clients this past year who wanted to use USAA, and once we got the Good Faith Estimates realized they were actually going to be charged more going through USAA than using a local lender.  I always suggest to my buyers to speak with two lenders and compare...who is going to give you a better rate, and charge fewer fees.  After all, this is your money Mr. and Mrs. Buyer.  You may get $1500 back at closing, but when you pay almost $700 in processing fees and then a higher interest rate, that $1500 really isn't that good of a deal.