<p>Yep. Because the <em>theory</em> goes:</p>

<ul>
<li>This is a poor answer, I will give it a -1</li>
<li>If they want to rid themselves of the -1's, then they should improve their answer with an edit</li>
<li>If they edit it, everyone who has previously voted can re-cast their vote</li>
<li>If they don't edit it, then the original reasoning for your vote still stands</li>
</ul>

<p>See for more info:</p>

<ul>
<li><a href="http://meta.stackexchange.com/questions/19021/request-change-in-behaviour-vote-too-old-to-be-changed-unless-post-is-edited">Request change in behaviour: Vote too old to be changed, unless post is edited</a></li>
<li><a href="http://meta.stackexchange.com/questions/6250/vote-too-old-to-be-changed-unless-post-is-edited">Vote too old to be changed, unless post is edited</a></li>
</ul>