I've been up on Cannon a few times so far this spring - Moby Grape once, Down East once, and then an abortive attempt on M.G. on a wet day. I definitely agree with what's been said about exercising some caution on Cannon, and also with Loran's feeling that it's not called for to avoid the entire cliff in the spring.
My (admittedly somewhat limited) experience has been that the trade routes (VMC, W-G, M.G) are generally reasonably solid, even in the spring, but that the sections of cliff that are generally loose and vegetated can be pretty nightmarish. When I did Down East the other day, I made the mistake of topping out rather than rapping after the slab pitch. The upper pitches were _much_ looser than usual, I thought. Or maybe I was just gripped after going for the big slide on the crux...hmm...
peace, and climb safe!