Thanks for the link, Kim. I went through the questionnaire and since I have acreage, I would be a slam-dunk for certification through no particular effort of my own. I have a large diversity of native plants providing both food and shelter, a year-round creek, wetlands, brush and rock piles, etc. As it all appears to be self-reporting, I think the purpose of the signage would be to heighten awareness, and I can see that in a city or suburban setting that would be much more effective than in a rural area. Going through the certification process may encourage folks with smaller lots to create a missing link (e.g., brush piles or water source) and posting an 'official' sign may start a conversation with neighbors about the importance of preserving wildlife habitat.
Ann, I was similarly surprised to find the fee structure at the end of the questionnaire, but there was no particular pressure to purchase, and by completing the questionnaire, one would have a better idea of what might be missing to be certified even if you choose not to do so. I wasn't offended.