Whether intune or other, there really should be something to alert the end user that an install is happening. The updates that supposedly don't require a restart in most cases do. Programs quit working correctly, sometimes work is lost, and productivity definitely is affected. Even if you don't provide an opt out opportunity, it would be beneficial to provide a 5 minute warning at least, or an option to delay if they are in an important meeting or trying to meet a critical deadline. These quiet installs are a big problem and cause most of our help desk calls. Loss of network connectivity, programs not responding correctly, etc..