I have also just watched the opening match between Brazil & Croatia, and for the duration of the match I have seen several times a non-gripped body attached to a Canon long white supertele, there appears to be several photographers with that setup scattered around the stadium. That is mildly interesting to me since I am used to seeing mostly 1-series bodies or (less commonly) the equivalent Nikon ones being used for matches at this level. I really don't think pros sent by wire agencies, big international newspapers and magazines to cover this event would be using 5D3s or, worse, 7Ds. At the very least they should be using a grip for better balance while using those superteles on these smaller bodies, if that's what they have to use, which I doubt.
OT: As for the match itself, I think that Jap referee erred in giving that very soft penalty that led to the 2nd Brazilian goal, that Brazilian player was already falling down even before he got a mild touch from the opposing Croat player. Ruined the game for me. I must say Brazil was unimpressive, I really expect better from the hosts and one of the favorites. They don't seem to be good at keeping possession or defense. I think they would get exposed by a better attacking team than Croatia. Croatia played better than I expected, I actually wanted them to win or at least get a draw, they deserved that at least.