I guess you could think of it that way... but it's a bit pointless.

I mean, I don't want to be involved in a car crash. So far I have not been involved in one, does that mean I'm anti-manifesting the car crash? Again, you could think of it that way but I'm not sure why you would want to.

'Manifestation' is a fairly arbitrary construct in itself, everything in our life is our creation (concious or otherwise), its just we tend to give conscious creations the name 'manifestation'. In other words, you're describing the exact same thing as manifesting when you introduce the concept of anti-manifesting; You desire a certain outcome... the outcome comes. The outcome can be anything, be that something tangible or in the case you describe in your question the absence of something tangible.

delving deeper, I would personally go on to say that more than pointless... the idea is foolish! It simply doesn't make sense to me... returning to the car crash example; I wouldn't focus my attention on the absence of car crashes in my life and then celebrate the fact that I wasn't in one thereafter (until I am). I think focusing on them at all risks more of them coming into my immediate experience. It's a bit like there being two paths, one which leads to a chest full of rewards, and the other which leads to a chest full of the exact same rewards but the path is covered in barbed wire and flames... It's a pointless risk to take.

And finally, just to address something you may have had in mind when you posed the question. I think it pertains to events you think are imminent and thus would require this "anti-manifestation' idea in order to negate it happening. No events are imminent, they are your creation remember through the thoughts you hold in your mind and how you feel about them. The best way to negate something you felt was coming is to stop feeling like its coming, and think other thoughts instead. You're essentially choosing to consciously create something else... which is just what we call 'manifesting'.

So with that said, I don't see the need for the idea of anti-manifesting in our arsenal at all.

maybe it is more complete
knowledge to seek
understanding the
connectedness of it all

what would it be then
that wish for it to be
our self-centered desires

or you tell me
what it is we all seek

You may want to play with manifesting, yes have fun creating. This may mean avoiding any kind of convoluted ideas. Not intentionally avoiding them just being too immersed in the play of creation. Blessings!