The authors leave out the most obvious explanation for that's going on. And instead argue that limits of gambling and drugs might also be ineffective. Children

The authors leave out the most obvious explanation for that's going on. And instead argue that limits of gambling and drugs might also be ineffective. Children can recognize that there is no major harm in playing games. Being forced to follow irrational rules leads to non-compliance. Rules around nicotine, drugs, and gambling do have a rational basis and do cause real harm. And for many people explaining this is effective in helping compliance.