torchello/knpbundles — comment on commit 7e71dfc57bb7f2d9fca1d9f5c80c67498fc41663
File: src/Knp/Bundle/KnpBundlesBundle/Controller/BundleController.php line 146
By mbontemps:

AFAIK this is bad practice: you have to send a 403 rather than a 300.