LowDrag
Contributor
Define messing with. If you mean presenting unbriefed scenarios like the instructor suddenly losing consciousness while giving an in water briefing, then yes. Have done that. If you mean actually harassing them, then no. Having a volunteer give less than accurate info as to where they last saw their missing buddy, just as a distressed diver who actually has lost their buddy may do, absolutely. If everything goes as expected it's not an actual rescue class. IMO.
As in turning off your air, pulling your mask off of your face and other such things.