Why not? My transaction with 0 fees went into the blockchain.. :O
Anyway wouldn't they at least cause massive amounts of traffic between miners etc?
Bitcoin has multiple different ways of preventing spam based on age (I don't recall age scheme off top of my head) and BTC value of tx. Maybe you could make an impact if you had 1M BTC.
Peers connected to you would simply reject your transaction if it doesn't meet the minimum fee (there are two potential minimum fees - a minimum fee to relay the transaction, and a minimum fee set by pools to actually include the tx in a block -- only in certain instances is the minimum 0BTC). Mining pools would likely never see them.
