why and the darkness within

Actually, I've long been considering something lately which is pertinent now in the sell side of FWL and FWLO, so maybe you can help me.

On the sell side of both the FP and ops there are very large orders that have been queued,with the effect of frightening the price down - understandably. After all, I know when I see an inordinately large sell order sitting there, I'm not likely to buy into it, but rather set my buy a few points down and let the panic bring the sale to me. And it works almost every time.

Which begs the question - why do people do it? They know a large sell order like that is going to frighten buyers away and depress the price AWAY from their sell - so why bother queuing the order?

If you're that desperate to sell, wouldn't you just sell into the buy-queue in dribs and drabs from off screen?

Some more paranoid posters call it 'capping'. But this too, I cannot see the sense of.

But then, perhaps I'm stupid. Can someone enlighten me?