With 'nervous passenger delays departure', if they did so twice in a row (two successive flights) or twice in a year? As costs rise, anything that can prevent a delay will be considered fair game. The
PR response along the lines of, "We have to consider the 300 pax that were delayed last time they booked with us".
If I'm right, we may see more prosecutions for cost of diverts when pax are disruptive. It is sometimes said that a divert can cost £25k.
From the BA listing (linked above) it appears that they have all the powers they need. The use of bold text is BAs.
7a38) If you have behaved in a way mentioned above on or in connection with a previous flight and we believe you may repeat this behaviour.
7b) Our right to refuse to carry you when we have banned you from our route network
7b1) We will be entitled to refuse to carry you or your baggage if weyou a banning notice and you have bought your ticket while the ban applies.
7b2) By a banning notice we mean a written notice we have given to youyou that you are banned from being carried on our route network. (This means you are banned from travelling on all flights we operate.) This notice will give the date when the ban comes into force and the period for which it applies. A banning notice will also ask you not to buy a ticket or ask or allow anyone to do so for you.
7b3) If you try to travel while a banning notice is in force, we will refuse to carry you and you will be entitled to an involuntary fare refund.