Does "Reserve Battery Level" in Windows perform any function besides the popup?

In Windows 7, when a system reaches the Reserve Battery Level, does the OS perform any function(s) besides showing a popup indicating that the Reserve Battery Level has been reached?

According to this source:

Reserve power means programs and the OS are prompted to begin saving to save program and system data, and/or switch to additional battery.

Yet this source states conflicting information:

I've ... checked several MS documents and the Reserve Battery Level merely initiates a warning notification [with no action].

So, which is it? Is Reserve Battery Level only a prompt for the user, or does the OS also perform other actions?

Solution 1:

The warning is nothing more than a message to the user to say "Hey, I'm about to have a forced shutdown. Save your data now, or plug me in."

There are several different options you can configure in the advanced power management settings. There are settings that are nothing more than mere warnings to a user, and there are other settings that will perform an action. The ones that perform actions are the settings for critical battery action and low battery action. With these two cases you have the options to Do nothing, sleep, hibernate, and shut down.

Solution 2:

Is Reserve Battery Level only a prompt for the user?

Alerts are give to users at 7% battery power (default value).

or does the OS also perform other actions?

The system will automatically hibernate at 5% battery power (default value).

This Technet Article from Microsoft should be a more reliable reference than the links in your question:

Windows 7 provides enhanced UI notifications to alert users when battery life notifications help users understand how much power is left in their portable computers’ batteries. In Windows 7, battery life notifications are more prominent, and they encourage users to connect to a power source before the computer automatically hibernates.

At 7 percent battery life, Windows 7 alerts users that the battery is entering Reserve Power mode and prompts them to connect to a power source.

Windows 7 automatically puts the computer in Hibernate mode when battery life is at 5 percent. IT pros can configure low battery thresholds by using Group Policy and Windows Management Instrumentation (WMI).

Source Longer Battery Life