I care what validators say or imply. The reason I started using UTF-8 in the first place, was because it is a W3C accessibility guideline to use UTF-8 over the more common (in that time) iso-8859-1.

If you want to create accessible websites, one of the first requirements is validated code.

If we ignore validators and the W3C, who is there to officially tell us what we _should_ do?

We are long past the point, sure, so much so, that W3C recommends it too.

And about browser support: If you want to guarantee that most browsers understand and support your code, your best bet is to adhere to the W3C that wrote the standard.