Odd request probably but get the odd occasion when sometimes staff manage to ring in like 100000x an order.
Not a round number like that though it is actually the number of their RFID fob without leading 0s.
Not sure how it happens as so far been unable to replicate given the RFID reader enters carriage return after number however am guessing they are swiping their fob at just the right time while pressing a button for it to get registered as number before carriage return.
Not helped probably by some of the girls using the rfid bracelets we trialed as reader is in front of till guessing its swipping while using the till.
It has only got as far as cashing off a few times in last year on quick sale transactions of single products where they ring in and press cash knowing the price and having the money already.
Just wondered if maybe there might be possible to sneak in an option to disable the qty numberpad option? 
Or obviously an alternate solution.
Expect I will get ‘move the rfid reader’ and similar suggestions and yes that would eliviate but it makes sense to have where it is for speed of use.
Could you add a constraint to the specific payments rules that numberpad value isnt greater than 99 then if the rfid scans at 100000 it shouldnt fire the rule but you can still enter quantities up to 99?
Then you would maybe also need an additonal action in those rules constraint to fire when numberpad exceeds 99 that resets the numberpad on screen to remove the vue scanned in?
But the numberpad is used for other features including local loyalty RFIDs so constraining numberpad entered rule.
Maybe just a order added rule where qty over 99 the auto cancel it might be simple patch.