And what happens when they ignore you? I've reached out to tons of website operators to ask for machine readable access to their data on academic, personal and professional projects, I have never gotten a reply and had to resort to scraping.
A previous company I worked for aggregated publicly recorded mortgage data. The mortgage data was scraped from municipal sites on a nightly basis because it was not available as a bulk download or purchasable option.
We had requested on several occasions for a service we could pay for in order to get a bulk download of this data, but the municipalities did not have the know how to provide this as were using systems from a private vendor that were prohibitively expensive for them to request modifications. As a result, we worked hand in glove with the municipalities to ensure we were not stressing their infrastructure when we did this scraping, and I think that's the best we were able to do in this case.