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!
That's why there some teams already migrated their public chat to the investors into the discord which already exploited by these scammers. I mean there is no bug like what was already happened in the slack channel and it seems to be a goot place to start another channel in the discord.