It has always been one of my worst nightmares.....especially with my son (he is 13 this month).... but when he was young and we where outside in the garden one afternoon, I turned my back to look at something.... when I turned round again he was gone!.... I have never felt such fear in my life... he was only 2 at the time, and decided that we wanted to go and see our neighbours ..... I found him up the lane (a long way up the lane!) with the dog!....I never let him out of my sight again, and from then on until he was old enough to understand the entrance gates remained padlocked.....
So it only takes a second and your attention to waver and poof they can be gone in a flash. When we where out and about, he was on child reins, which are the most sensible things invented for children.... gives you peace of mind and I think every parent should have a set.......I would never like to experience that fear again....