God I freaking hate that. I have had clients never get it, I keep telling them “we’re cc’ing the whole team here to keep all parties working on this in the loop” or whatever and they just couldn’t reply all. Such a pain in the ass.
We have massive distribution lists, often filled with other distribution lists, so we get the related problem of people accidentally emailing the group who need to know about x instead of the team that makes changes to x
Then people reply all and cc in the correct address, and people take the opportunity to email 700 people to let them know that someone accidentally emailed 700 people and that that's not on