Tile wouldn't be effective for this.

They are great for locating stuff you lost in your own house, but will have limited use for something like this....

You really need something with gps and cellular capabilities. I have something like this on a very expensive drone in case it gets "lost"

However, you will be paying for the device AND a monthly service fee for the cellular service.

I think a MUCH cheaper and easier solution for pinball machines is - good insurance.

Yup. I have tile- I use it all the time.

But you hit the issue- for it to work:
someone with the app on their phone has to walk in close proximity to it, and
have Bluetooth enabled at all times.

Someday, if millions use this app- it will be useful, but right now, its WAY too spotty to be used for tracking stolen items.