Best way to thank theater staff?

Last night there was an adults only preview of Toy Story 4 at 8:30PM at night. While in the theater waiting for another movie I watched two adults and a group of 10 children walk in to try and purchase tickets. There was a collective look of disappointment on the faces of all the people in line waiting, thinking they were now going to have to deal with kids in what should've been an adults only session.The staff informed the parents that this was adults only, and unfortunately they wouldn't be able to sell them tickets, that they could come back the next day. The mom took great offense to this and said that it is horrible they aren't letting the kids in, that the movie was for them and there shouldn't be an adults only show, that their kids had been "waiting years" for this movie (despite them being 5-6 at the oldest), she basically tried every guilt tactic in the book.The theater staff held their ground and kept refusing, even as the mother threatened to never come back with their kids ever again, and eventually left.They were still busy so I didn't want to interrupt them at the time, but I'm really grateful that they stood their ground and gave their other customers a good experience.What is the best way to thank them? A quick email to the store? In person to the manager? via /r/movies https://ift.tt/2x9CFD9