It is news when BA can restrict the above to CERTAIN TAs.. maybe to those who don't sell a lot of BA flights, or sell only discounted tickets.
Restricting based on location is one thing, that is inventory control. But to restrict sales, or prohibit viewing even based on any particular agency ID? Now that's sneaky ! And unfair...
Which is probably why BA went with Amadeus instead of Sabre. Sabre is restricted from such practices as it's based in US. Some US law prohibits it from this sort of anti-competitiveness.