1-5 printed on boarding passes, with the highest figure reserved for economy fares.
Maybe folk who book discounted flights will be in the 4/5 range. I fear for those with a 5, if it’s anything like the Virgin flight I was on last – they left people til last (like me and my son and another family) and tried* to say they would put us in whatever seat was available, which may not be together! The family had a 5 or 6 year old who they tried to sit separately! It wasn’t like we had bargain seats either – I’d paid full whack and booked mine well in advance. Bastards. I won’t be flying with Virgin again.
*Luckily, a nice chap moved seats so jr could sit with me.
BA seats are always assigned. Anyone flying with children should be assigned a seat beside them regardless.
Basically this is a no-story story, but everyone will have their own seat assigned before boarding. It wont be a free for all with first one getting first dibs of the best seats or anything like that. As people have mentioned, they already do prority boarding for higher flying classes anyway.
I suspect there may be an element of paying for priority boarding in the future though. Though paying to be fourth out of five isn’t exactly a easy sell, not exactly going to show everyone you’re a high-flyer (see what I did there?!) by spending a fiver getting on the plane five seconds before Joe Bloggs in economy and still having to walk past all the Club class people already quaffing their champers.