On Grading Presentation

When the third student gave his presentation while looking at his ppt, I found myself hesitating to tell him that he did not meet the requirement set at the beginning of the term--you cannot read.At the beginning of the term, to provide better opportunities for the students, and to bring more vitality to the classroom, I decided to ask them to give presentation and then grade them accordingly. The presentation went on well. Til one of the girls sang her song while looking at her ppt. That was against the rule. I asked her to redo it.And a next WOW group. Great music and too.And the third one, the geart one. The pictures were gorgeous. And it was at this moment I started to doubt, am I pushing them too hard by asking them not to look at their ppt while giving the presentation and limiting the ppt by allowing only outlines?Should I ever grade those against the rule? They also worked hard and did excellent jobs.But if I did so, is it fair to those doing it according to the law?I need your help.Thanks.