I'm currently looking for ways to get real estate listings in a particular area and apparently the only real solution is the scrape the few big online listing sites.
That’s one of the bigger ones. Unfortunately recent events means scraping is still a gray area.
https://en.m.wikipedia.org/wiki/Van_Buren_v._United_States
I think it only applies to systems that aren't available to the general public, which in this case was the GCIC. Anything that is available to the public, even if it requires some sort of registration, would I think be legal to scrape. YMMV though.
More related to the submission content -- at the time we used rotating proxies, both in-house & external (ProxyMesh - still exists & only good things to say about it); they allowed us to "pin" multiple requests to an IP or to fetch a new IP, etc...