Yes of course you're right, don't know what I was thinking.. But it doesn't really make much of a difference. Consider:

-USB or serial connection (What do you think the odds are a typical thief has broadband and a router)
-No router for it to talk thru (mine couldn't call anywhere if it tried)
-Static IP off their subnet or no DHCP server (thief connects, no mojo, tries USB instead, see above)
-Software upgrade erases Hijack
-I'm sure there's more

But let's assume it does reach the server.. what is it going to do?

-Give us the IP (quite likely dynamic and mostly meaningless, good luck getting PacBell to tell you who was using it at X time)
-Lock the empeg somehow (accidental tripping risk, software upgrade still clears, doesn't help you get it back and encourages them to destroy it)
-Tell the user that they've won a boat in the Police auction and to bring it down to the station to collect it (ow! my boating arm!)
-Your idea here

And don't forget we're still assuming that they know roughly what this thing they stole is, get it connected, find the software, etc before selling it off to some innocent person (and then IIRC the law isn't on our side even if you do find it.. wasn't there a discussion on this in one of the other theft threads?)