Well they are warned before submitting the vote. We actually changed it a while back so you get a pop up saying you are about to vote this game 0.5 are you sure you want to vote ? YES / NO. You have to click that to advance so no one can say they voted by accident.
In my opinion i think a lot of the 0.5 votes are just from people that cant even read English. They prolly think we're hosting the ROM so they just click around on the buttons in the post desperately trying to leech the game. Trust me i've had pm's from people asking where the download button is saying they clicked everything but cant find it.