Depends on context. If someone says that is happy to see his wife's mother when he's not in fact, I don't think it anyhow corresponds with trading risk with him. And if someone sais he will return you 2 cents in a week and hasn't return in a month it is another kind if lie: maybe 2 cents is not so much, but if a persom declared a deal and didn't follow the rules he declared by himself, this will be a totally different case.

Lie as an idea by itself doesn't say enough about trading risk. So I suppose that no, it is not appropriate to leave a negative tag just for lying. The one should show how can it be projected onto trading. If it has too few connections with trade, than it's not a Trust case on this forum.