One technique to increase your confidence in an area where you feel unsure is to imagine the worst complaint that might be made and then consider how you might deal with it.  You can use this technique in developing your own thinking and in staff training sessions. 

The advantages are:

• Talking about the problems others might raise enables exploration of difficult issues without anyone having to reveal their own personal views. 
• Sharing possible answers and coping mechanisms saves reinventing the wheel - if someone else has a good line you can use it too. 
• It will probably never happen but the fear of it happening has a very negative effect.  Thinking through like this gives a sense of being prepared 'just in case' which strengthens confidence overall.