Actually, you do have ways of knowing this. You can either ask or check their games in progress.
The poster shouldn't post ongoing games and the readers should not offer any advice or analysis to ongoing games.
When I read the thread, it is pretty clear that it was an ongoing game.
In this case, you should do research since to not do so runs the risk of breaking the rules.
On another thread a few other folks and I were accused of cheating because we responded to a post concerning King vs. King + Pawn endgame. We were accused of cheating because supposedly this game was still in progress. I agree that if you're in the middle of a game and post your game in hopes of someone giving you your next move that you are cheating. However, the people who are reading these posts have no way of knowing if this game is still on and therefore are not responsible for the posters bad behavior. If one of these people throws his/her two cents in, it doesn't make them cheaters. I don't think anyone should be expected to do research before they post their opinion in a forum. I post this because I'm deeply offended at being called a cheater at no fault of my own. I also think that there needs to be some sort of forum etiquette that says, "Only the original poster is responsible for cheating through posting." If I'm wrong about this I hope someone can clue me in on the reason why.
Anthony