an ethical contract

if any of the terms are breached you agree to being sued by any persons with adequate evidence that they have lost funds. without attempting to hide behind bankrupcy protections

the terms saying: (i kept it as laymans as possible)
you will only take funds from the transaction fee's not from people funds themselves
you will not allow unauthorised people into th server room or access to your admin gateway
you will not refuse to repay anyone.
will will have security that will be adequate to prevent hacking
in the event of a hack, if funds are lost. you will reimburse customers
(feel free to add more..)