Not sure which toys referring to, but over going two ways: 1, in some cases the lock is to big to fit through the tube, so just having it in while the cage is on is sufficient. 2, wear a pierce of your jewelry that can't be removed without the opening pliers and loop the lock through the jewelry at the end.
You can buy locks---on the cheap which won't fit through a cages bars. That said, you could always buy cheaper PA tube, providing you're 4 (5mm) and lower. The lower the gauge, the less the pressure. Jay
I have a piercing lock(integrated just like cage) that I can put on that is too thick to pull thru bars of cage, essentially making it impossible to pull out. There are two problems with this set up. 1. The lock itself is rather long, protruding out of cage making it easy to pinch if bumped left or right. 2. A lock with moving parts is no place for urine. Unless you want to run some water over it every time you pee, it will become corroded and removal of lock becomes difficult within days. It was a nice idea, and it's always available to use if needed, but not practical for long term use. Maybe for extra security if she was feeling you were cheating the cage or something, but really is uncomfortable when bumped or sit wrong. I have a picture of it in my gallery, if you don't mind the occasional pinch, and constant lock cleaning... it's as secure as it gets.
Yeah I almost lost a release when she tried to open it and it didn't open "oh well looks like you stay locked"