Hi V and welcome to the Shack!
I've used those same stands with the SBS-01's in my great room and my dedicated HT without any anchoring, but I don't have kids. None the less, attaching the speakers to the stand is not necessarily going to prevent little kids from knocking it over. Even mounted securely to the stand, the entire stand and speaker together would be easy to knock over by a kid.
Of all the speaker stands and speakers I've every purchased, which is quite a few, I've never seen any sort of anchor included. Those stands are not made by SVS, they are third party stands, thus I'm not sure we could expect anything other than what it is.