A consistency trap is the act of making a person state something, usually in the first person, and then forcing them to act in accordance to what they stated. To a degree, they will already act in accordance to it.
This is due to the principle of consistency. We are likely to continue doing what we already do, and act in accordance to it, because we don’t want to go back on our word or seem inconsistent.
It’s the basis for techniques such as: