I notice a lot of people I ride with 'cross chaining.' I tend to avoid it like the plague. Most systems today can handle it well with perhaps a little more wear on components and slight loss of efficiency.
I started riding road bikes in the early '70's when chains were a lot less flexible side to side. Even on a 5 cog block it was a little dicey going big-big. Nowadays, chains are a lot more flexible and can easily handle big-big. I still don't like to do it, but it's mostly out of habit.