The other thought is that gigglies and smoochies, etc. in restaurants even between a young guy and gal will get that same response from some kids (in fact it's even more likely to get comments of one sort or another from same kid :-)

And I've noticed that that same behavior in folks my age and older (though pre-true gray) gets wierd looks (as in 'don't you know better than to behave that way in public).

Of course, unless it's intense, the same thing when both are grey-haired pulls "Awww, isn't that sweet" responses.