Barney,
I expect that if the survey shows, as I anticipate it will, that the result of IVIG therapies in an overwhelming majority of SCLS patients who previously had repeated episodes has been few if any additional episodes, then its eventual publication ought to make it easier for all of us -- and particularly for the next generation of SCLS patients -- to receive, and be covered for, this expensive treatment earlier on after diagnosis.
Still, insurance and other approvals in the USA and elsewhere will likely remain on a case-by-case basis, and prescriptions of IVIG therapies to control SCLS will continue to be made on what is called "an off-label" basis.
The reason is that the gold standard for medical trials involves running "blind" experiments where some SCLS patients would be given IVIG and others would be told that they are -- but in fact they would be given a look-alike, harmless fluid like saline (salty water).
A survey of experience like this one surely helps, but it doesn't provide persuasive scientific evidence because it does not obtain results from a random sample of patients and an experiment under controlled conditions.
And yet, as one of my doctors has said, given what we already know through the RareShare grapevine, it would be ethically indefensible, at this point, to run such an experiment and give mere saline to an SCLS patient who has tried everything else and is still suffering from potentially lethal episodes.