Like others already posted, I, too, often check the backs. I just run my fingers down both sides of my lanyard and pinch each pin and back together going from top to bottom.
I've found that you have to be really careful on rides that shake you a lot, like Indy or Star Tours. I tuck my lanyard inside my shirt if I can and check all the pins before I exit the car.
Also be careful in situations like taking a jacket off, hugging someone, etc. when a pin might get pulled or loosened.
I've used the locking pin backs, but have found that even they can loosen and if they do, you can't tighten them back up without the little wrench, so I suggest that if you go to the locking backs, carry a couple of rubber backs in your pocket to use in an emergency if the locking back comes loose.
On Sat., I thought I'd lost one of my best pins! I looked down and it was gone
. It was after I'd fought through the crowd to get a locker on Main Street. I retraced my steps, but it was not to be found. We went over to CA, I rode the TOT, and we were standing in line for Aladdin (at least an hour had gone by). I went to open my fanny pack to put my sunglasses away and there was my pin...wedged between my tummy and the fanny pack!
Miracle!!
So there's another reason to wear a fanny pack, even though they're dorky, and to indulge in that piece of eggnog fudge. If it hadn't been for my tummy and fanny pack, my pin would have been gone for good!