Spam scripts are much less smart than that. I added a hidden field with no text in it to a contact form, and a polite warning as the hint text for accessibility

Spam scripts are much less smart than that. I added a hidden field with no text in it to a contact form, and a polite warning as the hint text for accessibility. If anything was filled into that field the submission was silently dropped. I was cc-ed on any entries, and I believe there were 0 spam emails in the 8 years or so that the form was up.