One of the scariest things a developer can hear from a new client is the infamous claim: “I know just enough to be dangerous.” Translation: I don’t really know much but I sure love to tinker with things! This always puts up a little red flag in my mind. However, a seemingly harmless bit of tinkering can have disastrous consequences on a live website.
One note of caution – You should only use these particular constants if you are your client’s sole developer with an agreement to maintain that site. Otherwise, you could be locking your client out of the freedoms that he needs to maintain his own site, should he choose a new developer. In most cases these healthy boundaries will help to keep your client safe from his predisposition to ill-advised and uninformed tinkering.