Is there any risk using extremely high Zindex in WPF XAML?

Question

I wonder if there is a risk of resource or performance when using super high ZIndex in a XAML view?

For exemple, is there a difference between this:

<Grid>
    <Rectangle Name="BigBoss" Canvas.ZIndex="1000000"/>
    <Rectangle Name="LitleBoss" Canvas.ZIndex="1000"/>
    <Rectangle Name="normalGuy" Canvas.ZIndex="2"/>
</Grid>

and this:

<Grid>
    <Rectangle Name="BigBoss" Canvas.ZIndex="2"/>
    <Rectangle Name="LitleBoss" Canvas.ZIndex="1"/>
    <Rectangle Name="normalGuy" Canvas.ZIndex="0"/>
</Grid>

I am not aware of the mechanic used behind ZIndex and how it is used to render the view but I assume that if there is a loop iterating every elements of the 1000000 "used" ZIndex, there would be clearly a performance issue.