All AzureAD Connect modules & scripts should be signed by Microsoft
In more restrictive environments powershell execution policy set to "AllSigned" is quite common.
Currently (AzureAD Connect Version 220.127.116.11) not all script/configuration files of AzureAD Connect Wizard are digitally signed by Microsoft. ADSYnc.psd1 is signed but AADConnector.psm1 is not signed.
-> Please sign all your Powershell script/configuration you deliver with AzureAD connect.