I have read numerous posts about the pre clock being inaccurate. I myself have experienced it, i've heard reasons from software to the clock in the tower is wrong.

So to get some real evidence I'd like to ask people to turn on airplane mode and leave their phone on overnight and see if the internal clock stays accurate.
Actually should also test airplane mode and phone off too but for this poll leave it on.

After performing the test myself I noticed between 1am-9am on airplane mode the time read 9:37 for 37minutes ahead then actual time. Post your results