I say you need to step up your counter-measures. Put the yoyo(s) in an area they canât easily get to.
Nice backpack, by the way. Makes me want to get one. It also looks like with the twin zipper pulls on some areas, locking it might be possible. I got a case recently and it has locking latches. An idea like that might be in order. I forget this one company that makes cases, but I have a couple used for holding CDâs and Iâm gonna yank that stuff out and re-line it with foam for carrying yoyos. It has a dial-type combo lock.
It also sounds like if you can, run a video camera to catch the thieves in the act. Present that to the principle.
However, at the same time, I always kept an eye on my stuff and was typically in control of it or it was locked in a locker(or my car when they took away lockers). I feel a bit more effort is required. Place items at the BOTTOM of the backpack so they have to DIG through it, which can mean time and/or noise. Put bells on the pulls so those can make some noise too. Although thatâs a bit too much.