All browsers should have this warning.

Warning: On the page you are about to visit, there is a built-in music player, and it’s damn hard to find the pause button.

Do you want to continue?

[] Don't ask me this again.
')
[Cancel] [Show web page]

Excellent results in tests on HTML5 and CSS3 - this is fine, what about such a useful warning mechanism?

via Gizmodo