I'm not sure spammers particularly care if they have a lot of email addresses that people don't really read. Google was already bouncing messages to invalid recipients, so completely nonexistent email addresses were already filtered.
Granted, it's one step further to know if you're getting past the spam filter. But I feel like that's testable using your own accounts.
Granted, it's one step further to know if you're getting past the spam filter. But I feel like that's testable using your own accounts.