TextureState.removeTexture() weirdness

If a mesh has TEXTURE0 and TEXTURE1 and I remove TEXTURE0 by TextureState.removeTexture(0),

then TextureState.getNumberOfSetTexture() still returns 2

Is it normal action?

In other words, Can we use OpenGL this way? (rendering with some texture slot empty)

I've noticed that as well, but haven't had a chance to look too deep yet. I would like to know as well.