It might be that they are trying to keep the patients relaxed whereby the effectiveness of the acupuncture can reach full potential. If you are tensed and stressed that sort of defeats the purpose of the acupuncture. More tension there is, the less able the Chi is to flow!

Regards,
Lobo-hotei
lobo

Treat the earth well, It was not given to you by your parents, It was loaned to you by your children.
Native American Proverb