I have a question. Why are you cancelling a raid when there's over 12 hours left for people to sign up? I mean, why cancel a raid on beforehand at all? There could be last-minute signups. But if you cancel the raid very early like this, you are preventing any possible signups that might have occured between now and the raid in 13 hours from now.
To let people sign up for the early raid, which also is short people, or would be without use signing up there.
Considering the past three Sunday raids have been cancelled due to lack of signups, some after the raid was scheduled to start, I don't think there is going to be a flurry of signups.
Especially since most of the people likely to sign up will be asleep for the next 6-8 hours too
Even more importantly: Planning security. If you're just a tiny bit short, the chances of success are good enough to try. But if it's a case where it's likely that those four sign-ups could now plan to do something productive (or fun, depending on how you look at it ) with their time, that is the best outcome given the circumstances.