A consistent source of angst from mobile phone users are the costs they often must incur to replace devices that get broken or damaged. Thanks to the subsidies mobile operators pay on handsets, they typically don't like to replace phones for free, asking users to pay up or renew their contracts. One key part of operators' arsenal in determining if damage has been caused by the user are liquid sensors. These little round stickers often reside under a phone's battery, and typically turn from white to some shade of red when they've been exposed to liquid. So if you've dropped your phone in a puddle and it stops working, the liquid sensor probably won't back up your story that your phone just all of a sudden stopped working. The iPhone is no different in this regard, but a San Francisco woman has sued Apple, alleging that the iPhone's sensors generate false positives, letting Apple skip out on warranty obligations
. The woman alleges she's had to replace her iPhone at her own expense twice, after the sensors showed her device had been exposed to water, even though it had not. For what it's worth, Apple says the sensors work just fine. This case may seem pretty pointless, but should the woman prevail, it could set a powerful precedent for all types of phones sold by carriers here in the US, and impact how they carry out their warranty replacement and service plans.