@GrumpenKraut "It came to my rescue that I brought my talk (outline) on paper, as I always do.....
..............Paper. Always. Works."
I hear you brother. Been there, done that, bought the T-shirt, read the book. Bringing some chalk with you in case they have something so impossibly old fashioned as a blackboard is not to be despised either.*
*Not so unlikely as you might think in the university sector where I work.