That's probably not the protection you think it is. It would be hard to prove that an agent that is pushing their own brokerage's properties is not doing their fiduciary duty unless they flat-out refused to show other properties, in which case you'd dump the agent. We have the same laws in our state, but having been an agent and a broker, I don't think it would change the behavior of such an agent. In my experience, an agent's main goal is to sell ANY property to get a commission -- unless the market is crazy, which it has been here, no agent would risk losing the entire commission to push a higher priced property. That said, they will show higher priced properties given the opportunity, which can be self-serving. Sometimes the buyer should refuse to view them if they don't want to pay that much, but sometimes the price is flexible and can be negotiated down to your budget, so you can get more house than you thought for not as much more as you'd expect.
In our area, there was a sense that if you belonged to a big brokerage, you'd have a better chance of getting your buyer's offer accepted for an in-house listing. In reality, that benefitted the broker, who would get a percentage of both the buying and selling agents' commissions, but it didn't do much for the agents. If I had a listing and an outside buyer's agent brought me a better offer, I'd advise my clients to go for the better offer, which could coincidentally be better for me if the price was higher. Again, the main goal was to close a deal.