Not to be unduly alarmist as some of this is a judgement call, but the green indicates the presence of solanine, a toxic compound. It develops along with chlorophyll in response to exposure to light.
The amount typically contained in a baking potato is enough to sicken a 100 lb. Person according to recent research quoted in a NY Times article.
Since some of the effects of solanine can be neurological, I prefer to err on the side of caution.
The majority of the solanine is found in the skin and immediately under it with very little in the rest of the potato flesh.
If I’m baking the potato, I just scoop out most of the flesh leaving a bit of margin near the skin. Or otherwise I peel them.
If I get a bag from the grocery with most of them green tainted, I’ll return it.
I just figure that with all the other pesticides and food additives out there gunking up
our food, many of which we can do little about, if there’s one which I can eliminate with very little effort, why not.
That’s my personal take on it.