I have often grappled with the conondrum of where the border runs in regards to when is a maze no longer a maze. This is not to say that what I consider to be a maze is the same standard that might apply to others, but I do have much experience in the art of making mazes and have tried to base my production on some of these various principles.
To begin with, I maze should only have one solution path which connects the entrance and exit of the maze, both of which should be based on the perimeter of the maze. There are several maze artists out there that have the maze end in the middle or somewhere in the blog of lines that they call a maze, but by strict definition these are labyrinths, not mazes, and are significantly easier to solve and do not make very good walking mazes.
A maze should not only have traps and confusing false starts at the entrance of the maze, but also from the end, as many users "cheat" by going to the end of the maze and working backwards. A seriese of traps from both directions will stump these kniving maze solvers.
Occasionally I will notice after I have completed the maze that there is more than one solution for PART OF THE PATH, that is two say the path forks and then meets up again shortly after. I consider this to be bad form in maze creation, but does not render it not a maze.