Telnet SMTP & Getting blacklisted

After I get MX records for a specific domain (nslookup -type=mx stackoverflow.com) I’m wondering if there are chances to get blacklisted.

I mean, I can always get a new IP address and that’s it, but I’d like to handle it much better.

For example, there are many tools that you can use to clean your newsletter list, verify email address etc., so I’m wondering how they handle this?

I can simply check if fake@stackoverflow.com, info@stackoverflow.com and team@stackoverflow.com exist:

root@verifier:~# telnet aspmx.l.google.com 25
Trying 74.125.22.27...
Connected to aspmx.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP 66si3380401qkt.189 - gsmtp
helo hi
250 mx.google.com at your service
mail from: <fake@fake.com>
250 2.1.0 OK 66si3380401qkt.189 - gsmtp
rcpt to: <fake@stackoverflow.com>
550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1  https://support.google.com/mail/?p=NoSuchUser 66si3380401qkt.189 - gsmtp
rcpt to: <info@stackoverflow.com>
550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1  https://support.google.com/mail/?p=NoSuchUser 66si3380401qkt.189 - gsmtp
rcpt to: <team@stackoverflow.com>
250 2.1.5 OK 66si3380401qkt.189 - gsmtp

Now we can see that team@stackoverflow.com actually exists, but I’m wondering how to handle to avoid getting blacklisted? Buying ​thousands of IP addresses and sending requests until each of them get blacklisted? Not a smart solution.

Thanks, N.