I am learning to fly (at BAFC, Wycombe), and I did have a trial lesson.
However, it is true to say that I had already decided to fly and that the t/l is not what made up my mind to do so...
For me, the t/l was part of the process I used to help me decide WHICH flying club I wanted to learn to fly with.
I'm very happy with my choice, by the way :-)
Andy