The beginning dancer may be unsure of his/her own ability and desirability as a dance partner. Sometimes the beginning follower can't believe that a more experienced leader would invite them to dance. If the follower is insecure in the invitation to dance it hints that her dance may be equally insecure. It sets the tone for a less than pleasant dance.
If someone invites you to dance, they have implicitly agreed to appreciate your current ability. I have had some very pleasant dances with beginners, and occasionally some less than pleasant dances with more experienced dancers. Even if you are a beginner, don't sell yourself short.
Don't use "who me?" as a response to a cabeceo. A better response is to either accept the cabeceo with a smile and a nod, or reject the cabeceo by looking away.
Please feel free to share your experiences and insights on this topic.