I suppose it all depends. If your customers are repeat customers and they are happy with the jobs, then it should not matter. If it is a new customer and he is happy with the job then also it should not matter.
The other side of the coin is that you are supposed to be the expert, and your customers might be familiar with color processing etc, if you are admitting here you dont even have a densitometer for process control, they might start to doubt your ability, even if you are turning out the best job possible and this might hurt you, simply because for important jobs they might start getting nervous.

I guess you have to balance what is more useful to you, if you are getting help, acquiring experience and learning more form the site then loosing a few customers might be worth it, in the long run you will become the expert, but if your bussiness situation is such that loosing one or two customers might represent 30% of your income then I would say it is not worth it and use the site only in emergencies.

Just remember, americans above all cultures I know admire "chutzpa." Dont forget, Bill Gates promised IBM an operating system when he did not even had it developed. So if you commit to a job and pull it through even if you had no idea how and your customers find out, they might admire you and trust you more. Good luck...