This is one of the hardest lessons to learn in business. Clients typically will want everything they can get, as I would totally expect and do when I am the client. Sometimes, however, no is the correct answer.
Being mindful of cognitive bias should permeate all aspects of your life, including work. It takes a lot of hard work to continually be aware of our cognitive biases, but can go a long way in solving problems.
Companies need to start treating their people as trustworthy, capable individuals. Not doing so contributes to why taking steps like the ones highlighted in this HBR article are rarely taken.