[Faith]

I know standing for your team the entire match is fun.
I know how annoying it is to have someone in front of you stand the entire match.

But depending on which side you are placed on and what the vendor is like, everything changes. I know that at regionals (at least in hockey rinks), the stands are steeper and when you stand it often only blocks a couple of people/rows. Hockey rinks often have different sections as well, so you may be standing and there is no one behind you to block. Also, at the regionals I've been to their is normally a standing area for teams that are playing.
All this makes it a lot easier to stand without disrupting someone else's view.

At championships, the angle is not steep (at all). I had trouble seeing the field over the heads of people sitting down sometimes, and when people in front of me stood up it totally destroyed my view. More people are likely to be there randomly/to see their (grand)child's robot/to see the team they are sponsoring that made it that far. (ex., my grandparents and my parents were there!) There is NO special standing area for teams who are playing.
It is really easy to prevent a lot of people from seeing anything by standing up.

Both of these situations are at FIRST competitions, but they are totally different. Teams should adapt to each competition (in my opinion).

Also, remember that depending on the situation, although you may only stand for 3 minutes per hour, other teams are standing during the other time and may be disrupting the same people.