err:XD0008 (more than one document in context) when not referring to the context

In XProc vNext; could it be allowed to have more than one document in the
context of a p:with-option, p:with-param and p:variable as long as you
don't refer to the context?

I have a step with this signature:

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" xmlns:pxi="
http://www.daisy.org/ns/pipeline/xproc/internal"
type="pxi:daisy202-to-epub3-content" version="1.0">
    <p:input port="content-flow" primary="true" sequence="true"/>
    <p:input port="resolve-links-mapping"/>
    <p:input port="ncc-navigation"/>
    <p:output port="content" sequence="true" primary="true"/>
    <p:output port="fileset" primary="false"/>

    <p:option name="publication-dir" required="true"/>
    <p:option name="content-dir" required="true"/>
    <p:option name="daisy-dir" required="true"/>
</p:declare-step>

As you see, the primary input is a sequence. So when I call it, I have to
do:

<pxi:daisy202-to-epub3-content>
    <p:with-option name="publication-dir" select="$publication-dir">
        <p:empty/>
    </p:with-option>
    <p:with-option name="content-dir" select="$content-dir">
        <p:empty/>
    </p:with-option>
    <p:with-option name="daisy-dir" select="$daisy-dir">
        <p:empty/>
    </p:with-option>
</pxi:daisy202-to-epub3-content>

As a script author I would expect that as long as I don't refer to the
context in a select expression, it wouldn't matter what is in the context.
(I didn't realize this until I encountered an input fileset resulting in
that multiple documents appeared on the steps input port, which means this
has been a bug in my script for a long time.)

This should have been sufficient:

<pxi:daisy202-to-epub3-content>
    <p:with-option name="publication-dir" select="$publication-dir"/>
    <p:with-option name="content-dir" select="$content-dir"/>
    <p:with-option name="daisy-dir" select="$daisy-dir"/>
</pxi:daisy202-to-epub3-content>

I find it strange that if there is no documents in the context it is only
an error if you try to refer to the context, while if there is multiple
documents in the context it is an error even if you don't refer to the
context.

What do you think?

Jostein