I had an acquaintance who was sued by Blizzard under the DMCA for creating a game server for StarCraft. That was under Vivendi which they are no longer a part of, so maybe it's different now, but I would not trust them myself.
The people mindcrime was talking about trusting are the creators of Nostalrius, not Blizzard — though of course Blizzard will threaten you for publicly running this program just like they did Nostalrius.
https://www.eff.org/cases/blizzard-v-bnetd