Incorrect VRN issues

Snakes_Belly

Why are ticket machines accepting incorrect VRN's and letting people pay with an incorrect VRN? Ticket machines now should be able to detect a wrong VRN and not accept payment. 

I was able to check online by inputing my VRN whether I needed to pay the clean zone charge. It must be possible for a pay machine to know whether the VRN is correct or not before accepting payment. 

This one rejects incorrect VRN's if correctly configured. Hat tip to Beaudelicious

Parkeon Strada Pal.

Fruitcake

I think you know why. 

Technology exists to prevent incorrect VRMs being entered, but if every PPC used them then they would make less money.

Southmead Hospital, Bristol, doesn't use a PPC, or it didn't the last time I was an inmate. It won't accept an incorrect one such that the exit barrier cannot be raised. It does have other problems in that the cuff of my jacket triggered the touch screen (which is actually a proximity screen) and I accidently entered incorrect characters. This is how I knew it wouldn't accept an incorrect VRM because it wouldn't let me out until it was correct.
There was also an onsite call button if you did have problems.