If you have the option of sitting vs standing, sit. Lots of people stand around talking between rounds and then complain about sore feet later in the day.
I may be in the minority, but I found the opposite to be true assuming I’m not carrying around a 20 pound bag on my back. Standing and more importantly walking around keeps the blood flowing and lets me stay loose. To each their own though, but I’ve never experienced sore feet at a tournament from standing but I have had a sore back and a tension headache from sitting hunched over and carrying a heavy backpack around.