The biggest problem with these hacks isn't a preference for CSS over JS (which IMO is fine in moderation); it's the fact that they aren't keyboard or screenread

The biggest problem with these hacks isn't a preference for CSS over JS (which IMO is fine in moderation); it's the fact that they aren't keyboard or screenreader accessible. A person using a screenreader can't even navigate to the accordion (http://jsfiddle.net/yn4ls/ http://jsfiddle.net/yn4ls/), and if they could, it would tell them it's a form element.