reminds me of when someone gave me a hug in Shul. i moved back and gently explained he probably didnt know that the Halachah to not kiss your children in Shul applies to adults as well and other forms of embrace such as hugging.
a few minutes later i asked a Tzaddik, Talmid Chochom who was also present, about this, just to be sure i did the right thing. he said the Halachah is as i understood it, but if someone hugs you in Shul, hug him back and dont say anything about it.