As a leftie I am instinctively opposed to this - vouchers seem condescending, needlessly punitive and, as some previous posters have mentioned, they have problems in terms of practicality. Yet whilst the freedom of those on benefits and their ability to purchase things like cigarettes doesn't concern me overly, the fact that some parents/guardians may spend too much money on this kind of thing and less on their children does - especially if the benefits in question are child benefits. One solution I can think of is all parents on benefits having to keep receipts to prove that they are spending enough money on food and necessities for their children - this could be a regular check-up for everyone or, more likely, be demanded randomly.