make big map
place bots
pokemon go
really?
nah what you really gotta do is make a client mod (totally would be able to fudge your location though, not that this is any different from actual pokemon go) that connects to some external server.
your client sends what BL server you're on and your location within the server to the blockland go server, and the blockland go server sends data back to the client to tell them if there's anything nearby, etc.