I never train people if they train me, I honestly just find that rude. Not everyone intentionally trains. At a higher level, would you like to keep that 1% (which just happens to be xxk) or not?
So yeah, a good advice is to keep on lookout and run away XD Where I used to be was a constantly trained spot, and I would be lucky if I saw under 3 trains there in an hour. However, I've memorized the path that monsters take to go back to their spawns so I rarely get killed by trains if I'm not lagging, LOL.