Ermmmmm, think about it.

Don't you think that the Hakurei's Shrine Maiden is no longer inside Gensoukyou?

What? Are you saying she's dead or something?

Noo, not that.

Right now, that Reimu has lost all of her Shrine Maiden's power, so she should be back to being a normal human, right?

When you tone down your spiritual power, it makes it easy for you to erase your tracks. So now that she lost her power, her spiritual wavelength should has changed as well.

If she's no longer a Hakurei's Shrine Maiden, she could have secretly removed herself out of Gensoukyou....!

Ah...!

I see.