I'm in favor of strict Vinaya adherence, but I have to wonder if the rule as stated above by Bhante can be circumvented by the Bhikkhu, who wishes to maintain the "hugging" connection with, say, his Mother, then instructs her that she may reach out to hug him, but not that he may hug her. Mom gets her hugs at will, and the Bhikkhu maintains this connection with his beloved Mother.
I wonder if this rule developed out of a concern, more than any other, that someone in the community would see a Bhikkhu hugging a woman, and believe something romantic or sexual was taking place. To rule out even the appearance of impropriety, the rule was established.
I can only imagine that there are some very solid Vinaya monks who still, while in a private home secluded from others, give their Mothers a hug. Going forth entails giving up so much, and with ( at least in the Thai tradition) the reverence that is paid to parents, that this is one area where some discretion can be applied, and maintain the Vinaya in the spirit, if not letter, of the rule.