This checkbox option located at the bottom of the place bets tab allows the customer to turn on and off the verify bets feature. When this feature is activated an extra page is displayed to allow you to check your stake, odds and selection before your bet is submitted.
Matched bets that have been cancelled by Betfair due to a change in market conditions. For example, in horseracing, all bets on a non-runner are declared void and will appear on your statement as void bets.