Policy tips in Exchange Online can be used for a lot of things: warnings if a user sends confidential information to someone outside the organization if a proper DLP policy is in place or other useful things. One simple and effective MailTip is available for a while now and helps to raise user awareness in writing e-mails.
Nothing special happens, only due to the fact that the MailTip is here the sender probably thinks twice: are all my recipients correct?
So, how to get that MailTips? Through Windows PowerShell of course!
First, connect to your Office 365 tenant with Exchange Online Remote PowerShell:
$cred = Get-Credential
Connect-MsolService -Credential $cred
$session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $cred -Authentication Basic -AllowRedirection
Import-PSSession $Session -AllowClobber
Afterwards set the Mailtip at the Organization Level:Set-OrganizationConfig -MailTipsExternalRecipientsTipsEnabled $true