Escrow Should be placed before awarding the project

Often it happens like a buyer awards the project especially in small projects freelancers tend to work on the projects and then later when a note is sent to buyer to complete payments they do not reply i think it will be better if scriptlance puts a rule to place escrow for the project before awarding the selected bid from a programmer like if buyer wants to select programmer a and the bid is $300 then it should be necessary to have $300 in escrow before awarding the project