ParNone - thank you for your interest - canine behaviour is my passion and, as the oldies here will tell you, I can rattle on for hours!!
They will also tell you that I have my absoloute no go areas - dogs on human beds and smelling a dog's feet being only two of many!! LOL.
I am sorry to say that feeding dogs human food is one of these. What you are, in fact, doing is rewarding your dogs for begging. It is very polite begging, I grant you, but begging all the same. By feeding them a little of the "reward" only sometimes you are reinforcing the behaviour even faster than if you fed every time. This is a classic method to smarten up a response that is flagging - start with a reward every time and when the dog knows the behaviour you want (be it sit, come or beg) give the reward only every two three or four times. This makes the dog try even harder to give you what you want in order to earn the reward.
The truly fantastic thing about companion dogs and the people that own them is the variety of lifestyle options and combinations. What is acceptable to me may be the one thing that you can not tolerate in your own dog, what you think is ordinary every day dog stuff might be the thing that is the number one no-no for me - as long as you are happy and the dogs in your life are safe, well and mentally sound then there is no need to fret about it. The science behind animal behaviour and research into it is a fast moving, ever changing and multi faced world and the tiniest discovery can have far reaching possibilities throughout the animal kingdom. Thank goodness there will always be something for us to talk about!