Well, I am glad my intentionally provocative comment finally attracted a response weeks after I posted it - I was just trying to get a debate going on a thread which had become something of a self-congratulatory love-in amongst run/walk devotees!
But, seriously, I don't have a problem with beginners walking: but their focus should be on quickly building endurance so that they no longer find it necessary.
This planned run/walk strategy for racing (in marathons in particular) is something which started in the USA and which has contributed to a general erosion in running standards over there. The median finishing time in many US marathons is now hovering around 4:30 (or slower) and a significant proportion of participants are finishing in well over 6 hours. OK - they may get around the course, but like I said, don't call them runners.
For me, running is about health, fitness, enjoyment, socialising, competition and - crucially - trying to realise one's potential. You will never do that if you set out on a run, planning to walk when you feel like it. I didn't see Paula R walk a single step in Chicago!
Happy running!