Interesting. I took the is= from something I saw in one of Eliot’s posts.
<If field=landarea more_than="{Get rangelow}" less_than_or_equal="{Get rangeone}">
On this post - If with variables - Loops & Logic - Tangible Talk
So just to see what happens - I put the following:
<If check="{Get name=autozonetest /}" is value="Yes">Y1
<Else />N1
</If>
<If check="{Get name=autozonetest /}" is="Yes">Y2
<Else />N2
</If>
Output on Page: Y1 Y2