The lid has around a millimeter of slack when seated. Putting my finger over the air hole stops the stream immediately. I can fill it 2/3, put my thumb over the spout and turn it upside down and the lid stays on.
I've never used a Yixing teapot, so I have no idea. I'd ask the vender but I don't want to embarrass myself, if dripping is normal at this price point.
