Yes? Duh? That's the point of anti-forgery laws.
In any case, dragging a 12 year old through the legal system seems like a greater harm than allowing them to play Roblox (although perhaps not by much).
A company could in theory ask for ID before selling any product (ignoring age discrimination laws), and you wouldn't say that a child is harmed if they use their fake ID to buy a bottle of water, for example, so the use of the fake ID doesn't necessarily lead to harm.