Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: IB+ Gold, TK E+, Hyatt Globalist, Marriott LTP, IHG Diamond
Posts: 14,170
Happened to me recently. No issues boarding...
I think the problem is that many other airlines print the e-ticket number on their BPs. So you get used to seeing a bunch of digits on your BPs.
Then BA comes along and prints "no coupon". And if you've ever arrived to an airport and the airline says your e-ticket hasn't been issued properly... then you're going to freak out seeing "no coupon". But that's just how BA does things...