I chose sedation for my colonscopys, flex sigs, and upper endoscopys HOWEVER it is not mandatory and people do it without sedation. I have a friend that gets them often due to a rare disease and she is tried of giving up an entire day each time to recover from sedation so she goes without. It's slightly painful, and very very uncomfortable, but it was worth it to her to not lose a day everytime.
I don't get them that often to worry about a day missed.
My insurance company, however, considers sedation on a colonoscopy to be elective and doesn't cover it!