Disallowed characters in URL and search

[eluser]victorche[/eluser]
Hello again ... I am facing a big problem with my future site logic. The problem is really simple. I really need the search query (keyword) to be in the link. This way users can send each other url-s with the search results, like
example.com/search/keywords_here
One other thing ... I really want to use opensearch (for info, check here: http://www.opensearch.org/)

And I am doing something like this (note, I am using urlencode):

Code:

if ($this->input->post('search'))
        {
            $search = $this->input->post('search');
            redirect('search/'.urlencode($search);
            return;
        }

The problem is, if someone puts disallowed characters, it shows error. First, I don't know what is the problem for just hitting on the keyboard and adding ">" symbol. I mean is there something connected with the security? I guess so, but anyway all the queries are checked and secured anyway. And if i have any worries about it, at least i want to be able to change this default CI error ... With something which suits my design.

To forbidden all is not always needed. And I really need more freedom here. Besides, this CI error is just unexeptable for my site design and idea.

Any help and ideas?