anyone can place bid\asks on mtgox and then cancel... does not cost money to do this.
how to bidding and asks placing work in other markets in the world?
Placing "bait" orders as well as pulling them to exploit various things happens "for real" / in the normal marketplace all the time.
I don't see the point in asking an entrance fee when there is a provision cost on transaction already.
Also since it is all electronical there is no real "cost" to place an order other than needing to track it, and so far we're still in manageable dimensions.
As for spread/comission/cost - if you create competition, obviously spread/fees/comission will go down.
Don't like it as it is? Tough titty. Pseudomonopoly ftw.