You'd need to provide more details. What were they were wearing? Last visual/phone contact? If they had smartphones try to get/guess their passwords from relatives and look at their Location History. If there was an iPhone amongst them find my iphone. If you can trace their IMEI numbers maybe it could help local police to track their last locations.
Sowohl Android Smartphones als auch iPhones bieten die Möglichkeit an es zu orten und aus der Ferne zu löschen.
I would recommend signing into your moms iCloud account and seeing if it last pinged from where it died. Even with this turned off I’m sure it still does this feature. I helped a lady at work with this very same thing who thought it was turned off :-) good luck!
Wait there's an iPhone? Use the FindMy app feature to track your phone and backpack BEFORE the battery goes dead. Hopefully someone just dropped it at the mall security desk.
If it makes you feel any better, I've never heard of anyone going out of their way to get someone's serial numbers. But your devices can't be tracked by a serial number alone, and unless they have your Apple ID login, your devices are protect by iCloud Find My Device.
Apple's marketing for it seems to be limited to this paragraph on their iCloud page. Generally for a lot of older devices what you have said is true, it's only devices that support Catalina (or iOS 13) or above which do. Funnily, the same feature is in Airpods.
I'm not sure if the system should be detailed more or not - part of what makes it secure and effective really is lack of awareness. Full details of the specifications are out there though, if a little tricky to find. I seem to get more details on the process rather than the technical implementation.
Also, with "Find My" system adds a level of security, I had forgotten about. You can stop someone from doing what I said.
https://www.apple.com/icloud/find-my/
So worth turning on with your Mac (enabling on the Mac).
No need to change your apple ID. You should put it in lost mode:
https://www.apple.com/icloud/find-my/
and your data is safe. But if you are really worried you can remotely erase it. But lost mode allows you to have a message on the screen including a phone number to call you should it be found.
iPhones have the find my phone feature. Android has apps like Prey but very few people bother to install it.
You have a chance of tracking it down if it's an iPhone.
You could try calling it, offering a reward.
Here is where I found the info -
You can set up notifications for when friends and family leave or arrive at a place — making meetups a cinch. And so no one’s privacy is compromised, they’ll be notified when you set one up. You can also use parental controls to set up alerts and notifications, so you know when your child has arrived at a friend’s house or departed from school.
​