Mobile Safari, the browser found on iPhones, iPod Touches and the iPad, does not (currently) implement the same label behaviour as other browsers. Clicking on labels doesn’t do anything—possibly, as Ben Darlow suggests, it is because it would interfere with the tap-to-select-text functionality, although personally I think that usability trumps obscure text-selection use cases.
What’s even weirder is that, in over an hour of googling, I couldn’t find a single reference to this issue. Surely someone, somewhere must have noticed that clicking or tapping on labels in forms on iPad doesn’t select the input? I resolved that when I published a fix for the issue, it would include a couple of clunky sentences stuffed with as many keywords related to the tap click form label input select checkbox radio button problem as possible…
via The Watchmaker Project – How to fix the broken iPad form label click issue. Nice and simple fix, defiantly not quite as common a problem on the iPhone (rarely do I find myself wanting to hit the label vs. the input field).