I find the entire premise of charging an employee for mistakes reprehensible. Unless you are underpricing your work and working on such a narrow margin that any errors are shoving you closer to the edge of bankruptcy, there just is no rationale for it in a modern society. Most of our grandparents fought long and hard to force the 8 hour work day, end child labor, sweatshops, unpaid overtime, the end of "company towns" where your rent, food, clothing was paid for out of your wages at highly inflated rates, etc... In fact, many of our country's agricultural workers still work under those type of conditions.
Stuff happens...... materials jam, vinyl runs crooked through the plotter and jams, etc., etc. Cheapskate employers also skimp on adequate tools, work areas, cutting areas, sharp blades, poor lighting, etc. all of which contribute to mistakes.
Nearly all of the materials we use most often cost pennies per square foot and an occasional full redo should still fall within the profit margin. That is unless the employee is both overpaid, slow as molasses and mistake prone.
Now if its user error mistakes that occur frequently with the same employee, then either retrain, shift duties or replace.