<font size="2">My apologies, I gave the wrong examples. Here are the corrected ones:<br><br></font><font size="2">If we were starting with a blank slate, it would be feasible to have
ß/ẞ kept separate from ss/SS (although note that the German national
standards body doesn't: the uppercase of ß is SS, which is why they got
connected in the first place in Unicode). Similarly, it would have been possible to separate σ/ς (again, joined because they have a common uppercase Σ).<br></font><font size="2">
<br>
<b>But we are not starting with a clean slate: </b>we are facing with changes to an
existing widely-deployed standard, over 6 years old, which is a long time in terms of the web. We have two effective options:</font><font size="2"><br>
</font>
<div><h4><font size="2"><a name="TOC-A.-Maintain-compatibility-with-IDNA"></a></font><font size="2">A. Maintain compatibility with IDNA2003</font></h4>
<table style="margin-left: 40px;" border="1" cellpadding="3" cellspacing="0">
<tbody>
<tr bgcolor="#cccccc">
<td><font size="2"><b>
URLs</b></font></td>
<td><font size="2"><b>
Result<br>
</b></font>
</td>
<td><font size="2"><b>When</b></font></td>
</tr>
<tr>
<td><font size="2"><a href="http://www.xn--mxads7ake1d.gr">http://www.γιατρός.gr</a><br><a href="http://www.xn--mxads7ake1d.gr">http://www.γιατρόσ.gr</a><br><a href="http://www.xn--mxads7ake1d.gr">http://www.ΓΙΑΤΡΌΣ.gr</a><br>
</font></td>
<td> <font size="2"><a href="http://www.%CE%B3%CE%B9%CE%B1%CF%84%CF%81%CF%8C%CF%83.gr/" rel="nofollow" target="_blank">http://www.xn--mxads7ake1d.gr</a></font></td>
<td><font size="2"><b>always</b></font>
</td>
</tr>
<tr>
<td><font size="2"><a href="http://www.weltfussball.at">http://www.weltfußball.at</a><br><a href="http://www.WELTFU">http://www.WELTFU</a>ẞBALL.at<br><a href="http://www.weltfussball.at">http://www.weltfussball.at</a><br>
<a href="http://www.WELTFUSSBALL.at">http://www.WELTFUSSBALL.at</a><br></font></td>
<td><font size="2"><a href="http://www.weltfussball.at/" rel="nofollow" target="_blank">http://www.weltfussball.at</a></font></td>
<td><font size="2"><b>always</b></font>
</td>
</tr>
</tbody>
</table>
<p style="margin-left: 40px;">
</p>
<h4><font size="2"><a name="TOC-B.-Deviate-from-IDNA2003"></a></font><font size="2">B. Deviate from IDNA2003</font></h4><font size="2">Try to separate them, leaving users with a de-facto indeterminant mapping. That results in the following:<br>
<br></font> <table style="margin-left: 40px;" border="1" cellpadding="3" cellspacing="0">
<tbody>
<tr bgcolor="#cccccc">
<td><font size="2"><b>
URLs</b></font></td>
<td><font size="2"><b>
Result<br>
</b></font>
</td>
<td><font size="2"><b>When</b></font></td>
</tr>
<tr>
<td rowspan="2"><font size="2"><a href="http://www.xn--mxads7ake1d.gr">http://www.γιατρός.gr</a></font></td>
<td><font size="2"><a href="http://www.xn--mxads7afk1d.gr/" rel="nofollow" target="_blank">http://www.xn--mxads7afk1d.gr</a></font></td>
<td style="color: rgb(153, 0, 0);"><font size="2"><b>sometimes</b></font>
</td>
</tr>
<tr>
<td> <font size="2"><a href="http://www.%CE%B3%CE%B9%CE%B1%CF%84%CF%81%CF%8C%CF%83.gr/" rel="nofollow" target="_blank">http://www.xn--mxads7ake1d.gr</a></font></td>
<td><font size="2"><b><span style="color: rgb(153, 0, 0);">sometimes</span></b><br>
</font>
</td>
</tr>
<tr>
<td><font size="2"><a href="http://www.xn--mxads7ake1d.gr">http://www.γιατρόσ.gr</a><br><a href="http://www.xn--mxads7ake1d.gr">http://www.ΓΙΑΤΡΌΣ.gr</a><br></font></td>
<td> <font size="2"><a href="http://www.%CE%B3%CE%B9%CE%B1%CF%84%CF%81%CF%8C%CF%83.gr/" rel="nofollow" target="_blank">http://www.xn--mxads7ake1d.gr</a></font></td>
<td><font size="2"><b>always</b><br>
</font>
</td>
</tr>
<tr>
<td rowspan="2"><font size="2"><a href="http://www.weltfussball.at">http://www.weltfußball.at</a><br><a href="http://www.WELTFU">http://www.WELTFU</a>ẞBALL.at<br></font></td>
<td><font size="2"><a href="http://www.xn--weltfuball-b4a.at/" rel="nofollow" target="_blank">http://www.xn--weltfuball-b4a.at</a></font></td>
<td><font size="2"><b><span style="color: rgb(153, 0, 0);">sometimes</span></b></font></td>
</tr>
<tr>
<td> <font size="2"><a href="http://www.weltfussball.at/" rel="nofollow" target="_blank">http://www.weltfussball.at</a></font></td>
<td><font size="2"><b><span style="color: rgb(153, 0, 0);">sometimes</span></b></font></td>
</tr>
<tr>
<td><font size="2"> <a href="http://www.weltfussball.at">http://www.weltfussball.at</a><br><a href="http://www.WELTFUSSBALL.at">http://www.WELTFUSSBALL.at</a><br></font></td>
<td> <font size="2"><a href="http://www.weltfussball.at/" rel="nofollow" target="_blank">http://www.weltfussball.at</a></font></td>
<td><font size="2"><b>always</b></font></td>
</tr>
</tbody>
</table>
<div style="margin-left: 40px;"><font size="2"><br>
</font>
</div>
<font size="2">Why would this happen? Well, for some indefinite
period
time, both IDNA2003 and IDNA2008 clients will exist. So you get on a
friend's machine, go to your bank site, and get to a spoof site.
Moreover, in
an effort to maintain compatibility for clients, most
client-software will do a dual lookup; first try one then the other. If
someone comes in with an intervening registration, for a spoof site,
then a URL that used to work for you now leads to the spoof site.<br></font></div><font size="2">
<br>
Now perhaps the NICs for de, at, and ch will address </font><font size="2">ß/ẞ/ss/SS (and the NIC for gr will address </font><font size="2"> σ/ς/Σ</font><font size="2">)</font><font size="2"> by bundling
or blocking. But bundling or blocking defeats the purpose of separating
them, and there is little reason to think that .com, .biz, .whatever
will all do the same -- not to speak of the many, many more
registries below the top level.<br></font>