`//TRANSLIT` - than you need `iconv` explicit
`//IGNORE` - I  tested converting an `utf-8` string with one invalid character into `iso-8859-1`:
 - `mbstring` ignores the invalid character and doesn't trigger an error
 - `iconv` stops converting on the invalid character and triggers a notice. With `//IGNORE` it ignores the invalid character but triggers a notice, too

So I could add `//IGNORE` automatically on every convert because truncating the string to convert helps nobody.

What do you think ?