They would remain encoded in the url. ``/`` is all we need to fix the urls.
Now that you asked me that, I went looking for the CakePHP way of forming urls with the following tests...
```php
<?php 
	$id = 'test/with/ space/and:everything/漢字/látíñ';
	echo $this->Html->link('link', array(
	    'action' => 'show', 
	    $id)); 
	echo $this->Html->link('link', array(
	    'action' => 'show', 
	    'test' => $id)); 
	echo $this->Html->link('link', array(
	    'action' => 'show', 
	    '#' => $id)); 
```

Results as is now: (First and second links are broken)
```html
<a href="/pages/test%2Fwith%2F%20space%2Fand%3Aeverything%2F%E6%BC%A2%E5%AD%97%2Fl%C3%A1t%C3%AD%C3%B1">link</a>
<a href="/pages/test:test%2Fwith%2F%20space%2Fand%3Aeverything%2F%E6%BC%A2%E5%AD%97%2Fl%C3%A1t%C3%AD%C3%B1">link</a>
<a href="/pages#test/with/ space/and:everything/漢字/látíñ">link</a>
```


With that line: ``$out = str_replace('%2F', '/', $out);`` (This works!)
```html
<a href="/pages/test/with/%20space/and%3Aeverything/%E6%BC%A2%E5%AD%97/l%C3%A1t%C3%AD%C3%B1">link</a>
<a href="/pages/test:test/with/%20space/and%3Aeverything/%E6%BC%A2%E5%AD%97/l%C3%A1t%C3%AD%C3%B1">link</a>
<a href="/pages#test/with/ space/and:everything/漢字/látíñ">link</a>
```


If we change it to ``urldecode()``:
(This works for me too but old browsers may not be able to understand this and I think this is out of url standards. Better not...)
```html
<a href="/pages/test/with/ space/and:everything/漢字/látíñ">link</a>
<a href="/pages/test:test/with/ space/and:everything/漢字/látíñ">link</a>
<a href="/pages#test/with/ space/and:everything/漢字/látíñ">link</a>
```