I was riding with 16 others, no one else suffered anything
Yeah but that's how flats normally happen. It only takes one sharp edge to flick up. You don't normally get a bunch ride where all 10 people puncture. It could've been cut earlier and only let go on that ride too.
Aye, Merlin who I got them from have shrugged it off as "probably something sharp got caught*" but have thankfully passed it onto their distributor.
*I think this is bullshit, I was riding with 16 others, no one else suffered anything and yeah, there was nothing which obviously caused the tear.
I have done some reading up on those Schwalbe Ones and they seem really well-regarded, I might get a stash of them!