After looting the Orcs' ebony mine, I headed to the top of Throat of the World to mine the ebony there. Didn't have my armor or weapon with me to save space for the ores, and it's about the most barren place in Skyrim anyway. Well, the Orcs hired thugs to come after me and they saw a golden opportunity to catch me with my pants down. Oh were they wrong...

http://www.youtube.com/watch?v=Mc0sJj8SsFc

I befriended the orcs and have them make me bloodkin. Got into the mine for free. I can go into any orc stronghold now whenever I want. I don't get this senseless killing.

Nice. I robbed Arcadia's alchemy shop and as I and the guards of Whiterun were off to slay the first dragon in the main quest 3 thugs jumped me. Needless to say they didn't accomplish their mission. I found the contract on a corpse signed by Arcadia. I have no idea how she knew it was me but now she has to die for her actions

Wen I went into the stronghold I wasn't attacked or anything, and I took the ebony ore without them caring.
I didn't know you had to befriend them.
How do you do this?

Yeah, the Orcs wont outright attack you but I checked the thugs and they had a contract from Gadba gro-Largash from Narzulbur, the settlement the mine is at. Apparently they didn't like me mining after all.

First thugs I ran into were in Riverwood, hired by Dorthe. The blacksmith's daughter, the little girl......

Anyways I've had a few lucky dragon attacks as well. Dark Brotherhood major spoiler

If you're an orc, it's not a problem.

If you're any other race, then the sentry by the gate will tell you to get lost since you're neither orc nor bloodkin. You can ask if you can become bloodkin, and she will tell you to get the Forgemaster's Fingers from a nearby cave. You go, kill like 7 conjurers and get the gloves and bring them back. She'll tell you to give them to the chief, and he'll declare you bloodkin of all orcs, and you gain access to every orc stronghold in the game.