Who exactly is the victim of the crime which such a law creates? If the purpose of age verification is ostensibly to protect children, and if children are the ones lying about their age, then are they both the perpetrator and the victim?
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).
If a child is using a fake ID to buy cigarettes and alcohol, the harm they suffer is not from owning or presenting the ID, but from consuming the product which the ID gives them access to.
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.
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).