Most of what we do in life and business is done without legal or contractual cover.  In this wild majority of situations you are trading with your integrity.  Your integrity and the effect it has on your overall reputation is incalculable.

The supreme quality for leadership is unquestionably integrity. Without it, no real success is possible, no matter whether it is on a section gang, a football field, in an army, or in an office. Dwight D. Eisenhower

My integrity means everything to me.  When I make a commitment I want people to feel they can take it to the bank.