Competing with the Advice of Your Buyer's Mother's Brother's Nephew's Friend

We do the very best that we can do to make sure our buyers make informed decision and understand the process.  Afterall, it's what we do day in and day out.  I couldn't tell you squat about the best way to manufacture or sell widgets.  But I can

1. Explain what to expect during the homebuying process
2. Prepare comps to help buyers determine an acceptance offer on price.
3. Give buyers names of lenders that may be able to help with financing
4. Point out possible deficiencies in a particular house that may work against the buyer's best interest
5. Do my best to show them homes that they can afford and are well within their price range
6. Explain the advantages (few) and disadvantages (many) of short sales and foreclosures for the owner occupant buyer
7. Advise them on selecting a home inspector and possible concerns to have the inspector address

The list goes on and on but the point is that as agents, we do a host of things for our buyers but one of the hardest things to conquer (at least for me) is how to compete with the bad advice of the buyer's family and friends.

UNCLE JIMMY RAISES CHICKENS, CUTS HAIR AND OFFERS REAL ESTATE ADVICE
I'm pretty thorough in my research and good at breaking down explanations and justifcations so that my buyer can understand.  And I will definitely give my buyer the best advice and information available based on my diligent research efforts.  I often have to repeat information and I don't mind that.  But I don't stand a chance when it is evident that the buyer is receiving counterproductive information from "Uncle Jimmy" who clearly wants to impress with his perceived knowledge of real estate and prove how savvy he is.  Often offering up such ridiculous advice as "What?  They asking $39,900 for that ($100,000) house.  I wouldn't pay that.  Look at that filthy carpet. I wouldn't give 'em more than $25k."  This is overexaggerated but you get the point.

FROM BUYER'S AGENT TO TRANSACTION BROKER
Buyers then become overzealous and often unreasonable.  They become frustrated because now the agent is the enemy and agents become frustrated because we don't want to drive a wedge between us and our buyer's support system and end the end watch them make terrible choices.

At this point, I pretty much feel like a transaction broker only available to complete the paperwork and keep my mouth shut.

What are we to do?