How can we claim any high ground when we are handing off the need to check for plagiarism to a tool that in effect is the same as the student using it to create

How can we claim any high ground when we are handing off the need to check for plagiarism to a tool that in effect is the same as the student using it to create plagiarized works. It doesn't even work, its non deterministic, and most importantly - if the teacher is familiar with the student's writing it should be pretty obvious if this is a fake or not based on something they can be observed doing.