1-We are talking about the evolving spirits and not about the evolved ones. The latter souls could override the Karma. However completely evolved souls do not require earthly experience and as such is outside the purview of this post.( Hope You agree!)
2-The point that you brought in " The collective Vs Personal Karma " is interesting. I am still puzzled by the phenomenon.( The reaction(?) of Karma that one attempts to alter is based on personal observation and experience and I need to find a logical frame work for it!
). However I feel once I interfere in anyone's Karma that might become part of my Karma .)
3-And the last point.. being a master I could short cut and get away being acceptable.... is irrelevant for the ordinary souls.( refer point.1)