I seriously doubt any valid statistic exists for a claim about Spring being accident season. You'd need something like "accidents per 1000 season-active climbers" in order to tell, say , whether there are more accidents in the summer or just more people climbing in the summer with the same accident rate as in the Spring.
It is possible that various rock structures affected by cold and frost action might be poised to fail in the Spring, although I think that in the Gunks we've seen a similar effect from heavy rains.
Any kind of fixed gear is more than usually suspect, since it has seen a lot of weathering and little to no testing.
Lowering off a single in-situ fixed piece isn't a great idea at any time of year.