I use a stroller cable lock looped through the back wheel and connected to the frame. The CM's can still move the stroller, and it isn't that difficult to move it with only one wheel locked when it's empty with no kid in it, I've tried it myself to be sure. But you definitely couldn't walk a long distance with it or put anything heavy in it like a kid and then walk, with one wheel not turning it would be way too difficult. Hopefully that is enough to keep someone from just simply walking off with the stroller either by mistake or otherwise. There is no way a rental stroller would be comfortable enough for my 10 month old to nap in so I'm not taking any chances with my nice comfy stroller. It's not an expensive stroller, but it is soft and reclines and has darkening shades over the canopy. I also loop a stroller cable lock through my diaper bag and lock that to the frame. I only keep clothes, diapers and baby food in it but without it our day in the park would be ruined. If I had to miss a fastpass or ADR because of going to the baby care center for baby food or having to go all the way back to the hotel for clothes I would be ticked! my expensive stuff like cell phone and camera I carry with me at all times. Our city zoo is awesome and we go there all the time, but they have a big problem with theft of strollers and belongings. This is why I have my stroller outfitted with locks and such. I have to the leave stroller behind when we ride the little zoo train and for some of the exhibits and I don't want to have to worry too much. those little cable locks wouldn't be too hard to cut with the right tool, but hopefully people walking by would notice someone cutting a lock off and get security before they got too far, I know I would!