BA are not stupid, whilst not recommended if you do it once or twice it probably wouldn’t be affected though the advice is complete your booking as ticketed as there is always the risk as the fare for the journey you undertake will be significantly higher than the fare you paid.

At one stage they were passing the fare difference to travel agents via an ADM and they could ultimately stop them issueing BA tickets,

These fares red have been pulled pretty quickly is there any chance it was an error fare in which case they will be auto cancelled at some stage over the next few days bearing in mind we have a four day holiday weekend in the UK now?