Taking a BP

I went to the doctor two weeks ago and when she takes my bp I pull up my sleeve and she says to me "you don't do that,that could alter your reading". She also said"You should know that,you are a nurse right?" She might have been a recent immigrant,so I just figured that maybe she didn't understand she just said an ignorant remark about my skills.Since WHEN did this change about the bp? I,my co workers,bosses all have rolled up patients sleeves and then out the bp cuff on. As a matter of fact,that was my first time seeing it done that way.