Doing anything at restart is problematic at best because the ConfigMgr client agent isn't started yet.
Your best bet for this, depending upon exactly what it is, is to use a scheduled task.
No, ConfigMgr does not see a logon at start up any differently at all. As mentioned, ConfigMgr is *not* running at startup so it can't do anything at all.
If your challenge is to deploy software and ensure old versions (or dependencies) are not running, then running at startup is an inconvenient work-around at best. You should prompt the user to close those apps/dependencies. This can be done with the PowerShell Application Deployment Toolkit:
http://psappdeploytoolkit.com/ (or something similar).