I try to incorporate students as part of the team, with the understanding that as a team, we all do things that are low yield but help out in patient care. I don't ask students to get my coffee but I will ask someone to go get a final read while I take care of something else, so we can multitask as a team. Or ask to write out the h&p while I take the history verbally. Or ask them to do a focused physical while I look up labs and radiology. Stuff like that. If that is considered abusive then abuse ceases to have real meaning.
As far as starting on the night if the shelf, that is kind of tough cookies. Life in surgery is umpredictable and you need to know how to minimize the impact of stuff like that by studying in advance. We all know residents who had to take the Absite postcall.