I think the whole thing is a scam.
Yeah, just watch - tomorrow will be nothing but "security updates."
If KB3081424 ends up being SR1, that will be pretty disappointing. Aul's tweet made it sound as though it wasn't, but who knows.
The cumulative update we got on the 5th and SR1 are two different things. SR1 is supposed to be much larger and for Insiders, cause a full reinstall of Windows just like when new builds came out during the preview phase. For other users it is just another Windows Update.
I updated on the 5th without any problems but that was just the cumulative one.