Photo's from two of my clients yesterday. The liner was a touch up for a client who wanted a "thicker liner". The brows were a client who had "no brows" at all, as you can see. The bottom photo's shows no brow and just microblading. The middle photo shows microblading and shading. The shading was done with my new Xion and it gives the brow a very real appearance. If you look close then I also added some darker microblading after taking the first picture. This is added to the spine to create some dimension. Shading also helps the longevity of the brow.
So to answer the question, you can tattoo eyebrows and make the look so natural that most people will think they are real!