Whoa -- IOS6 Safari Caching

I've often suspected that Chrome did cache rather too tenaciously, although I am not 100% on that. But it seems iOS6 has gone beyond the whole hog, and caches HTTP POST requests:

http://stackoverflow.com/questions/12506897/is-safari-on-ios-6-caching-ajax-results

Whoa. Well, this kind of thing is a reason to be _very_ explicit in our HTTP response headers. Let's always set the Cache-Control header. Cache-Control: no-cache is a good default. For POSTs, at least.