In the 'olden days', when APTIS and SPORTIS machines were around, it was done manually, and the payment button on the machine was for 'Warrant'. I don't ever recall the ticket seller entering the RTVs code into the machine- it was simply cancelled by a station stamp.
These days, with the likes of FasTIS, the clerk enters the RTVs code to validate it. I am not certain an AVANTIX machine (the guards on train ticket machine) requests the voucher code though, as I could of sworn I've seen people use vouchers to buy tickets on trains. I can't think of an example where I've bought a ticket on an AVANTIX with an RTV though - so I stand to be corrected! (Yorkie may remember if I actually used one when I bought a ticket on GC last year!?)
not in my experience, and you have to give your name as well.
Yes, but 'giving' your name means writing it in the space provided on the reverse of the voucher, along with From / To station, and the number of the issued ticket- they obviously don't expect people to buy rangers of rovers with them though, as what do you put in the from & to box if buying a rover!? 'From Coast & Peaks, To Coast & Peaks'??