How do you explain the boundaries of hugging to a ten-year-old?

I am a nanny for a ten-year old that is constantly wanting hugs for every reason. Full, squish your guts out hugs and hang-off-you while you're trying to walk. At first it was cute, but its gotten to the point its actually making me uncomfortable but she and the parents are offended when I say "please don't do that." since she's "just showing affection."I have tried to explain boundaries, as I can bearly walk in a straight line without the kid wanting to hang off me for hugs, but now she is "air hugging" me everywhere I go and then "surprise hugging" me whenever I'm busy with something like dishes or cooking,How do you explain you a ten year old to respect boundaries in that aspect? via /r/Parenting http://bit.ly/2UuPr8N