It does have the benefit of keeping out spam and petty proposals, but if someone fronts the money and the Masternodes vote no, they are out a lot of money now. I don't think that's the way Dash wants to treat its fans, personally. Maybe keep the proposal cost fairly high like 2.5 Dash and refund 50% of failed proposals? That way there is still a risk for bad or scam proposals.
The fee can remain or even increase as one mentioned on here, very good sound logic,
But, God forbid, if their proposal fails, give it all back, it's the right thing to do.
What's wonderful is that person most likely went from fiat -> Bitcoin, Ethereum,Litecoin -> DASH.
Give them their DASH back and they can even convert back to fiat, but that's a lot of steps and waiting time for banks to receive the fiat payment. Betting the overall majority say screw that and hold on to their righteously refunded DASH as a long term investment or cryptocurrency purchase. Now they are cursing your name and wishing ill will upon you or the whole DASH project late into the night, all for not refunding their funding attempt on a legitimate idea which supports DASH.
Give it all back, sound business practices, you'll come out a winner in this slow and steady race.