Is A/B testing the color of your button ethically acceptable?
When doing A/B tests with the color of your button you are not trying to improve the quality of the goal behind the button nor are you trying to improve the explanation of why your visitors would be better of with that what you have to offer. Too me it sounds like you are trying to trigger the subconscious mind faster to take action, so the conscious mind has less time to make a decision. In that case using A/B tests for determining the color of buttons is strictly for maximizing profits and not improving the life of your visitors.