There is another eye lining risk which is easily avoided. Because of the anatomy of the eye, the technician should not tattoo in the outer corner between the lashes to join them together, or you run a significant risk of pigment fanning. That is where pigment will travel under the skin and appear beneath the eye as a bluish shadow. A qualified technician should tell you about this before beginning your eye lining procedure. That will be determined largely by the artistic skills of the technician.
Technicians come to the practice of permanent makeup from various backgrounds.
People come to me because I bring twenty years experience in making women look their best with conventional cosmetics to my work in permanent makeup. Sometimes, one or two hair stokes can make the difference between great brows and so-so ones. Even regular tattooists often don't do the best work in permanent makeup, unless they also bring a background in art or cosmetology to their work. Anybody can learn to run an autoclave. The bottom line is that you can't rely on the degree on the wall to determine if the technician is likely to do a good job.