Setup files that can get around UAC

I just downloaded an old edition of burnaware_free.exe, version 2.3.3, from here:http://www.digital-digest.com/softwa..._free.exe.html

and noticed that when I was logged in as a standard user (not admin) it does not trigger a UAC prompt and allows me to install the application even though I am not running elevated. Typically a setup file in such a circumstance would trigger a UAC prompt with the message: "To continue, type and administrator password and then click Yes."

By contrast version 3.0.1 triggers a UAC prompt for standard users attempting to install it : http://www.digital-digest.com/softwa..._free.exe.html

I looked at all the security settings although I could not work out what was set to turn off UAC for the setup file. Is it common, and what do I look for to determine if a setup file is designed to get around UAC? Could it be a simple manifest issue?