The thought of a magical girl being stopped by police like this is quite amusing.
If you want to hear something amusing, may I propose to you homebrew rules for the tabletop game World of Darkness? There are quite a lot of work about the hunters from Hunter: the Reckoning having to deal with the girls/women from Princess: the Hopeful. It is a very difficult and rocky cooperation since hunters tend to have a zero tolerance policy toward supernatural monsters, no matter their situation, whereas the pricesses are pretty much powered by hope, making them extremely tolerant and idealistic.