I'm pretty sure "Iron Man", along with everything else that wasn't already in C#, was down-tuned when I saw Sabbath in 2004 and 2005. (And it was definitely down-tuned when Dio was in the band.) And I highly doubt 98% of the people noticed, let alone rioted, especially considering a shit ton of old Sabbath material is already in C# (Or in Dio's case, Eb.) Plus songs like "Black Sabbath" lend themselves to down-tuning. I mean, in the end you're literally getting upset over a half-step/one-step change in tuning. That's literally playing one key lower on a piano.
As an aside, I'd also bet that when Ian Gillan was in Black Sabbath that when they covered "Smoke in the Water" it was probably slightly down-tuned too.
I eagerly await reports of rioting.
(Also: if this Ozzy set list remains, I'm thinking I may have to see the Halford/Ozzy tour.)