[Closed] Anyone used those car insurance driving apps?

Just wondering if anyone genuinely has got an extra % off the quoted price for driving carefully for x hundred miles? and, has anyone actually been given a gold star and the full discount? Seems to me it would be far too easy to take it easy for x hundred miles and then just revert to your normal driving style thereafter. On top of that, seems you could choose when to record that milage ie when you're not in a hurry. Just seems a bit too easy to beat the system for it to be a genuine route to upto 20% discount.