I'm not sure I understand why you would require an email to see a product tour???? I've reread your post 2x and it is not clear. If this is the case, I agree

I'm not sure I understand why you would require an email to see a product tour???? I've reread your post 2x and it is not clear. If this is the case, I agree - bad idea. Another thing you can do as incremental is provide dummy data or fixed queries which give them a taste of the UI but not with their data.