There are dynamic IP DNS blocklists and they are usually pretty accurate. Also, usually, your reverse name is pretty telling with home ISPs. Sure, you might be

There are dynamic IP DNS blocklists and they are usually pretty accurate. Also, usually, your reverse name is pretty telling with home ISPs. Sure, you might be lucky with a small ISP, but then, with a small ISP, chances are they wouldn't mind giving you "static" addresses anyway. Though indeed it would be an interesting experiment how domain and IP reputation actually interact at large email providers.