Mine/Tunnel Concern

In minecraft everyone knows that there will me underground networks all over the land, but what happens when two unrelated ones meet?

Today i was digging my tunnel and I found that i tunneled near the giant network that Beau, Tom, Josh, Minoko, Ferret, etc.(not sure if this is accurate) have collectively tunneled.

I just want to tell anyone who stumbles into my tunnels, please dont harvest, cause i sometimes leave gold, diamond, and redstone there becuase i dont dig with anything better than a stone pickaxe a lot.

Thank You!

Speaking by experience on other servers I have played on. Usually when I come across a tunnel belonging to someone else I either change direction or I go over top/underneath the tunnel. I try not to interfere with the integrity of the other person's tunnel at all. The only difference they may notice is I place cobblestone in places where I accidentally make holes in their tunnel.