This is just me but I've never really gotten the cancelling/postponing a fishing tournament. I've always kind of thought that if at least two people want to fish, let them go at it. This is usually what would happen with my club, especially with tourneys close to our home base. We'd stick with our plans, even though there would be some guys worried about falling behind in points and they'd try to get everyone to cancel it just because of that.
And yes, I've been one of those guys in those two man tourneys.
For tourneys farther away, around 30-60 miles, we'd usually cancel it if we didn't have at least two boats or four people. My club's always been kind of small, averaging around 4-7 boats per tourney. A big tourney's when 9-10 boats show up.
When you change things around at the last minute, that always affects some people who might not be able to make it. And that can be unfair in itself, too.