But, it is true that people run/walk a marathon? Right now I am training using the runkeeper app at a 4 min walk 2 min run pace, 2x a week for 35 minutes and one day a long run. I went my farthest distance and longest time ever at 4.41 miles in 1 hour. But do people really walk? Just really self conscious listening to how every runs, but never run/walk.
Disney races are probably the king of run / walk due to their official relationship with Jeff Galloway. I wouldn't worry about it.
Now, if you were at Boston, you may get some raised eyebrows, but even then it wouldn't surprise me that there are a bunch of run / walkers. Just a guess on my part.