Ah yes, this is what my friend told me as well, it's likely that she is avoiding to pay tax that's why she didn't want to stamp it. Is there any way I can check without asking her directly? Or should I ask her and tell her that I'm gonna go report her? Hahahaha. If she's paying then I'll be on the losing side though, but if she's not paying, well then......

Is the fine a lot for such cases?