I understand the purpose of a group hug, but I have always felt that it was the duty of the nobles and peers and officers and people in charge of things to go to as many of the workers official and unofficial and thank them personally. If a rain storm has come in the night and you come on site and you find people whose own tent has been destroyed putting up your tent. I think a thank you is in order by the people in charge. When we have under 30 people working on something I do not think it is impossible to thank most of them personally or in small groups and look each one in the eye. Yes, we might miss someone, but if we give out thank yous through out the activity and after the activity we should be able to catch the majority. Especially if your second and third in command is doing the same. 
A smile and a thank you is not that hard. My husband walks into kitchens and thanks the cooks and servers  for their work.  I walk by list tables and heralds and thank them. I am just a noble of the kingdom and a peer but I will try to smile and thank people when I see good work. I do this in groups and events where I have no contact. These people made something for me. I owe them personal thanks. 
I believe this is not something of rank. have seen the  Lady of Falconrose give Largess for good heralding and work. She isn't  a noble. She is a Lady of Ansteorra and she understands that all of us have a duty as Lords and Ladies to thank people who do the work that makes our activities possible. My sons when they were eight would run up and give toasts to the cooks or flowers to marshals or toll workers or water bearers for their good work. I believe thank yous from non nobles or peers or officers often mean more because they come from the heart not duty.  
Willow de wisp