I was not suggesting that everyone with a clingy child has created the situation themselves. As a mother of a reasonably independant and stubborn young boy, I am only to aware that sentiments that suggest you made him that way are annoying (although if I back off for a minute, I haven't ever discouraged ds from having an opinion, so I am sure that a little bit of his behaviour (positive and negative) is a result of my influence - how could it not be? Also, I do think that some behaviour is learned, (note I didn't say "taught") from our parents. I have a lovely friend who is extremely shy and quiet in social situations and her eldest dd is exactly the same (nature or nurture?). Whilst I am shy in some situations, I tend to overcome this by being more extroverted (maybe a result of moving around alot growing up and having to force myself to get along with different people) and so my son sees me go into social situations, even with people I don't know, with a certain type of confidence, so his main example is of someone who doesn't shy away from new situations (or, with all the moving, I would never have had any friends!)
I completely agree that forcing a shy/clingy child will probably only backfire, and that it is better to work with the child, rather than against him. I would suggest HEAPING on the praise whenever the ds accomplishes something independant, whilst not discouraging but "ignoring" the clingy behaviour: ie let the ds come to her, but don't comment on the behaviour or show undue concern for the child's shyness. "oh what is wrong darling, it's ok, mummy's here" type responses are understandable, but they do suggest to the child that there is something to worry about in strange situations. Maybe she should acknowledge he is there, say something positive about the situation,"those children look like they are having fun" type thing, and then carry on with what she is doing.