Is it an overstay if my passport is stamped for January 15 and I fly out on that same day?

The consensus in the comments suggests that if your passport is stamped for January 15, it is acceptable to fly out on the same day without incurring an overstay. Travelers must ensure they pass through immigration before midnight (11:59 PM) on January 15 to avoid any issues. Overstays of one day typically result in a fine, but many users report that fines for one-day overstays are often waived, showing variability in enforcement.