We faced a problem with our Lordmancer II Slack channel. There were many scam messages every day: in private, in general channels, etc. We constantly banned those spammers, but they just registered once again (even the names were the same!). Also each day we saw new members with names like "CEO", "cofounder", etc.
Finally we dicided to close the Slack channel. Now we use Telegram group
https://t.me/lm2ico as a main communication channel.
I strongly recommend not to use Slack for ICO campaigns!
ICO based slack channels run rampant with phishing scams, mostly disguised as the slackbot itself. If you happen to receive a private message regarding your myetherwallet, don't bother clicking the link, because most phishing scams rely on social engineering, in order to work. That means, you end up providing the hacker all the information they need, by doing so voluntary, but often unknowingly, due to the nature of the scheme.