Yes, but keep in mind nobody else has claimed, and the two people who have died are (apparently) vanilla townies. Logic would dictate that the secret nature of the ballot gives an advantage to the mafia to begin with, and if all that's been killed so far are vanilla townies, it's fairly reasonable to assume that the overall powerlevel of the town is low (few power roles, in other words).That's a small enough ability that the mod could give to a mafia player without making them too powerful.
Also, how much sense is it for the mafia to spy on votes? It makes more sense as a town ability than a mafia ability to me.