By handing out NFC stickers, bracelets, or cards for one month for free when boarding will make it so the majority of the customers that ride everyday have a NFC sticker that they can refill by tapping at any station that prints tickets, or their mobile phone. NFC stickers cost between .10 to .25 cents usd... They are programmable and you can reload the balance. So as long as the sticker is on them and loaded it should clear the sensor, if you design the NFC sticker in a cool silicone bracelet in multiple colors like a collectable and give free rides rewards for using it(10 free rides so that the person can form a habit, people need to perform an act at least7 times before it becomes habit) then you will stop the slowing down of checking tickets...