As explained to the user, bets that vary significantly are (automatically) voided within a 30min period, this is not a new rule, in fact it is enforced for more than 1 year to all users. The system is triggered only on less than 0.1% of all bets placed, and does not apply to live events. Virtually it's very unlikely that a regular user will see it, unless someone is trying to exploit odds's spikes because pre-live odds simply don't vary 10% usually.
Odds that vary for either direction are voided, and not only for the BetBTC's side. It is a 100% automatic process that requires no admin intervention (as on every BetBTC routines, except big withdrawals when admin intervention is called)
For transparency's sake, can we have an example of when bets were voided from the odds shifting in either direction? In fact, if you were able to find a zig-zag pattern in the odds where one player's odds were lower and another player's odds were higher by 10% each, then that would give much more credence to your claim of objectivity.