It's not the sort of thing that shows up as scheduled news. That's precisely the point. Intervention has little lasting impact if everyone knows it's coming.
Even now the SNB, BIS and ECB are all declining to comment, even though the SNB was earlier talking about intervention (in terms of the market not getting too fixated on certain levels and that there's no hard and fast 'line in the sand' and the BIS show up in their own name on the toy (or, rather, toys plural as there seemed to be the same pattern in Currenex as in EBS). Definitely there in EBS though.
So the denials are all about preserving the last bits of mystery.