Spammy Joins Get Your Domain Knocked?

[popawoody]

Question...
If bots are joining your site and using some known good email list of people they have collected, would enough of these joins cause your site to be knocked as spammy by the email progs like gmail, live, outlook and hotmail etc?



I ask this question after noticing bots joining my tube and considering what happens. Let's say the bot uses your email to join my tube. You would get an email from my domain welcoming you and asking you to confirm your email. At this point since you did not visit or join my site you either delete or mark as spam if not report my domain. If this is done enough wouldn't it make all emails from your domain be known as spammy and digging a little deeper couldn't hurt serps?

In my case I suspect a weak captcha and have shut down the join system until I sort it out. But I signed up for some other sites and noticed their join mails went directly to the junk email folders on at least hotmail.

Also I suspect this to be a sabotage tactic.

Any thoughts on the matter?