This has been the case on HBO/Basic fares on every flight of that type I have taken this year. Last year I only took CE or normal fare flights so I don't know exactly when this became the case or even if it ever wasn't the case. It does say that seats will be allocated to you (rather than you can choose) at Check In for the HBO fares on ba.com and separately for the normal fares says one of the benefits is seat selection - so I think the wording is relatively clear. To be fair to BA (and Alex) the Basic fare is there to give you the option of choosing to go without the added extras for a cheaper ticket. Sometimes the difference between the two fare types in ET can be huge and sometimes it can be £10 each way - at which point you have to wonder if it's worth it for all the restrictions.