Add issue related to how multiple payment instruments are handled.
--- a/latest/use-cases/index.html Sun Jan 18 19:04:41 2015 -0500
+++ b/latest/use-cases/index.html Sun Jan 18 19:32:55 2015 -0500
@@ -366,6 +366,17 @@
<tref title="merchant">merchants</tref>.
</li>
</ul>
+
+ <p class="issue">
+How are multiple payment instruments handled? Is there such a thing? There are
+two main approaches so far. The first is to treat loyalty cards, coupons,
+discount cards, and other similar items as types of
+<tref title="credential">credentials</tref> and the
+<tref>payment instrument</tref> as the mechanism that moves the value. The
+second is to explore how multiple payment instruments may be mixed together
+from different providers to complete a transaction.
+ </p>
+
</section>
<section>