it might be a case of the glass half full or half empty...all about perspective...
since there has been no cases of wild polio in the united states since thelate 70's and there have been no cases of natural polio reported in the entire western hemisphere since 1991. (except for haiti) And all the cases to come up have been from the oral vaccine or brought by travellers.... cave's book indicates that between 80-1985 there was somethinglike 55 cases imported. anyway, for me I would say that N.S. is ahead of the curve by not recommending it.
you can double check "What your Doctor may not tell you about children's vaccinations by Deborah Cave."
or "The VAccine guide" by randall neustadeter
my feeling is why do that to the body if it is not a real threat... of course if you are going to haiti or parts of africa and certain parts of india and asia, you might re-think it.. but really I think N.S. is showing some smarts..
happy researching.