another content negotiation question

and the objective is not to start another long philosophical thread :P and
it may be a very dumb question

What are the drawbacks of this simple solution.

in PHP for example:

if($_SERVER['HTTP_ACCEPT'] == "application/rdf+xml" ){
    header('Content-type: application/rdf+xml');
    echo "......."
}
else{
    echo "...."
}

I did this at http://www.juansequeda.com/id/

However, there is a difference when it is /id and /id/. When I dereference
http://www.juansequeda.com/id I get a 301 (Moved Permanently) but with
http://www.juansequeda.com/id/ I get 200 (and everything validated by
Vapour!).

As this ever been discussed? I can obviously see the drawback of having /id/
vs /id .

Comments?

Juan Sequeda, Ph.D Student
Dept. of Computer Sciences
The University of Texas at Austin
www.juansequeda.com
www.semanticwebaustin.org