I don't remember if it was a VT220 or VT320 that did it but I had to use one in undergrad computer lab (also connected to some kind of DEC running ultrix) where

I don't remember if it was a VT220 or VT320 that did it but I had to use one in undergrad computer lab (also connected to some kind of DEC running ultrix) where whenever emacs did a screen redraw (for example if you did a page down with C-v) it would go into I-search mode because something in the terminfo had a C-s to freeze the screen (before some more commands and then a C-q to un-freeze), and this was visible to emacs. Anyway what I'm trying to say is just as I'm glad I didn't have to use punch cards, I'm glad that the youth don't have to deal with that kind of nonsense.