As part of responsible training it would be in everybody's best interest to supply hearing protection to this pitman. Modern T/R motors ( & many others) damage hearing, guaranteed. Although the small foam earplugs are better than nothing, no earplugs WILL result in permanent hearing loss. Bring the youngsters up right & correct the mistakes by not ignoring hearing safety... we owe it to them. Good luck!
Cheers, Paul (now permanently hearing impaired, & NOT liking it one bit)