Mine has run several times, been lost four times.
I use a wrist strap now, and will continue to until I know she won't run. The panic never hits until you see them, the whole time you are running (and I'm disabled and struggle to walk) calling their name, asking faces if they've seen a little girl. And that moment you see them, it's like waves breaking on the shore, every single emotion you held back just comes out.
She's on watch at school as a hider. She'll creep into the bushes and ignore her name being called. She'll also run off if you upset her. I was known to leave the school premises as a little one if I was upset, so I wouldn't put it past her.
I have had the police involved once in the town centre. They both bolted in the shop, one four year old on purpose, and the six year old trying to help. Except the four year old ran out the shop and I was at the entrance waiting. Grabbed at her, then heard the panicked screaming of my six year old and turned to call his name, and she was gone. Had to get him and call 999 as she has no danger awareness and this time I really couldn't run. She just thought the whole thing was a jolly jape, and no one around her stepped in, they could have saved the police a whole lot of trouble.
Then the time she got out the house in the night, to go on a jaunt, she managed to circumnavigate two locks to get out, and one turned door handle that was above her high. She was brought back by the police after knocking on a neighbour's door. I don't know if I have recovered from the shock months later. I thought it was her, playing the lets knock and see mummy go answer the door game, went in her room and the bed was empty. Little toerag thinks I, look in boys room and bathroom - nothing - start to panic as door knocks. Rush though front room all lit up and kitchen to the door, I'm crying now typing it, so I guess you can see, that they are precious and a wrist strap can be a life save. And some of them need alarms, extra locks, hidden keys, and a wrist strap, and still manage to scare the life out of you.
I am actually scared to leave the house alone with her. She's four and a half.