Mercifully on a large grass area a good 500m away from the crowdline or anything aircraft related.
I doubt RIAT has that luxury of empty space.
However, people complaining about sport at an airshow you probably need to remember this forum if a self-selecting sample. It makes up hardcore air enthusiasts in the main. However, this demographic makes up a tiny tiny percentage of the actual people through the gates on a given day. Most are semi interested or just going as a one off take-the-family day event and aren't overly interested in the details and all out flying. These people will want the world cup and potentially may not attend if its not available.
The number of people at Yeovilton who just sat in their tents on the crowdline reading books and watching iPlayer whilst constantly ignoring the majority of flying was amazing. Some came, saw the red arrows went "ive seen the reds now, i can go home".
Personally id rather the football wasn't on free TV at all. Any football, not just the world cup but i realise in the UK im in a minority there!