I have added a CAPTCHA to the create user form, because users were being registered with random info.

The form looks like this:
<p>{{ user_form template="register.tpl" submit_button="Create User" }}
<table>
<tr><td>Name:</td><td>{{ camp_edit object="user" attribute="name" }}</td></tr>
<tr><td>Username:</td><td>{{ camp_edit object="user" attribute="uname" }}</td></tr>
<tr><td>Password:</td><td>{{ camp_edit object="user" attribute="password" }}</td></tr>
<tr><td>Password again:</td><td>{{ camp_edit object="user" attribute="passwordagain" }}</td></tr>
<tr><td>E-Mail:</td><td>{{ camp_edit object="user" attribute="email" }}</td></tr>
<tr><td>City:</td><td>{{ camp_edit object="user" attribute="city" }}</td></tr>
<tr><td>Country:</td><td>{{ camp_select object="user" attribute="country" }}</td></tr>
<tr><td>Phone:</td><td>{{ camp_edit object="user" attribute="phone" }}</td></tr>
<tr><td colspan="2"><img src="{{ captcha_image_link }}"></td></tr>
<tr><td>Code:</td><td>{{ camp_edit object="captcha" attribute="code" }}</td></tr>
</td><td colspan="2">{{ /user_form }}</td>
</table>
</p>

But the "code" field doesn't work. Type in anything or leave it blank, the user will still be registered. How do I validate the CAPTCHA?

The register.tpl template looks like this:
{{ if $campsite->edit_user_action->defined }}
{{ if $campsite->edit_user_action->ok }}
<p>User registered successfully</p>
{{ else }}
<p class="error">Could not add user: {{
$campsite->edit_user_action->error_message }}</p>
{{ include file="registerform.tpl" }}
{{ /if }}
{{ else }}
{{ include file="registerform.tpl" }}
{{ /if }}

(Version: Campsite 3.4.3)