Mmm the CF7 documentation doesn’t explicitly say ’email’ but for me it was implied with:
Contact Form 7 can also utilize it to blacklist specific words or IP addresses.
The warning you get that something is wrong can be changed on the ‘messages’ tab of the CF7 form. It’s the one that’s titled “Submission was referred to as spam”
Sent to trash: true, that’s what happens with blog posts comments. But CF7 uses the same blacklist and it’s documentation says
Put one word or IP address per line in the text box. Messages containing the word or sent from the IP address in the list you’ve created will be treated as spam by Contact Form 7 and will not be delivered.
Read here: https://contactform7.com/comment-blacklist/