As has been rightly said, so called Duty of Care can extend to evrything you do
e.g. Class D airpace, 2 VFR, having been given the required traffic info continue towards each other at the same level. You are sitting watching them on Radar........
I work with people who regularly say ' thats not my responsibility'. Unfortunately, today it appears to be that if you are aware of it and can do something sbout it, then it is your responsibility.