I think my iPad can be tracked without Wifi or internet connection

Long story short, my iPad was stolen last Friday, I have been tracking it since yesterday, and yesterday I activated completely lost mode (which I believe was a dumb thing to do) so I entered the passcode required for it to work and left a message. Well, now I can't track it because it will not connect to any kind of network, BUT as I believe, it will activate the location things.

Now with the last thing, las Friday when my iPad was stolen, just for practice and to see what happens, I activated lost mode with an iPad mini of my family, since then, today I checked it, and yes it is not online, it doesn't connect to any kind of internet, but I can see the head of the arrow of the location thing. So I logged into iCloud with the mail linked to this iPad and saw that indeed, the page said that this iPad was located 3 hours ago in my house, AND NOT EVEN CONNECTED TO WIFI. So now I believe find my iPhone might work even without being connected to the internet, only that it will be more slowly, because I can't see where it is in real time.

I'm going to take this iPad tomorrow to a place where it has never been connected and see if it stills send its location. I don't know how it happened, but it can help me to find mine, since my iPad is in Lost mode.

None of them have a SIM card to connect, mine is 3G + Wifi I think, but doesnt have the SIM.