Well, if you made it more like the real thing, it would be a lot easier for the student:
What Drowning Really Looks Like. Here is a quote from that DAN article:
"The popular conception of what drowning looks like is not accurate. Unlike this photo, drowning people usually can’t call out for help, and there is very little splashing or waving. Drowning is actually a very quiet and undramatic action."
In the Rescue Course, students are indeed taught how to approach a thrashing diver, even though that is extremely rare. If you are going to go beyond that and risk the student's well being, you are likely going even farther from the real thing and would indeed be worthy of prosecution. For example, when I took the rescue course and approached a fellow student simulating panic, I did as I was taught and used the method of diving down to swim below the student and come up behind him. When I did, he dived down after me, and he tackled me at a depth of about 4 feet. As the instructor was quick to point out, a panicked diver on the surface would never do that. They are struggling to stay on the surface, and they will not intentionally dive below it.
One of the things you learn is that a diver thrashing about on the surface is in no danger. If you think it is too dangerous to approach, then wait until the diver gets tired.
If you take a course you learn those things.