Try submitting a URL from the following domains, and it will be automatically flagged (but you can't see it's flagged unless you log out):
- archive.is
- watcher.guru
- stacker.news
- zerohedge.com
- freebeacon.com
- thefederalist.com
- breitbart.comEdit: about 67k sites are banned on HN. Here's a random selection of 10 of them:
vodlockertv.com
biggboss.org
infoocode.com
newyorkpersonalinjuryattorneyblog.com
moringajuice.wordpress.com
surrogacymumbai.com
maximizedlivingdrlabrecque.com
radio.com
gossipcare.com
tecteem.comI don't think that makes sense. The supposed spammers can just try looking up whether their submissions show up or not when not logged in.