Why would one omit the close tag?

Question

I keep reading it is poor practice to use the PHP close tag ?> at the end of the file. The header problem seems irrelevant in the following context (and this

Answer 1

It isn't a tag…

But if you have it, you risk having white space after it.

If you then use it as an include at the top of a document, you could end up inserting white space (i.e. content) before you attempt to send HTTP headers … which isn't allowed.