It was my understanding that HipChat would make private logs easily available to any administrator of the company account in the same way that public chat logs were available. It was also made clear that this was not something which could be disabled, otherwise impeded, or a user would be notified of. (somebody correct me on this if things are different)
On Slack, from what they describe, the feature is only available with a certain type of account, you can only export logs in bulk (i.e. it's not something easy to do, it has been made for a specific purpose), and employees will be notified if the feature is enabled/used.
On Slack, from what they describe, the feature is only available with a certain type of account, you can only export logs in bulk (i.e. it's not something easy to do, it has been made for a specific purpose), and employees will be notified if the feature is enabled/used.