The diplomat shares the time, for that evening, about an hour before sundown. He'll notice flaws with his invisibility glamour, almost immediately; it makes him difficult to see, but blurs things seen through him, making his outline visible, still, especially while moving. He also still kicks up dust, and he'll notice he still casts a shadow, as he slips away. Effective in a darkened area, certainly, but of far less use in an open, well-lit area, until he gets better at the spell.