There has yet to be anyone who has discussed any experience with IKO instructor's insurance.
Don't think I'd want to test any of these insurance policies in anger really. That said, the OP was asking about riders insurance and that's a major reason for joining the BKSA in the UK...because it includes a basic insurance policy. Some beaches are restricted if you don't at least have public liability insurance....so being a member of the BKSA in the UK is normally worthwhile. I can't...ahem....comment on whether or not they're otherwise good for the sport as I don't really know. I don't think the IKO offer a standard rider insurance package (not in the UK anyway) although I think they are offering instructor / school insurance....though there are a few other insurance providers around that seem to offer pretty good school / instructor policies (Bridle Insurance being one).