It sounds like you were on an Economy Light type fare, my first experience with not being able to select a seat free at check-in was probably Wizz, but I figured that was coming, it was a surprise when BA did it to me.

That said, (and thanks for the heads up there) how militant were they with the hand baggage? On my outbound trip to europe I weighed my carry on and it was like 10.5kg, I can easily drop it a little bit by wearing my jeans rather than packing them and I'm flying from Tirana to Belgrade, so I think it might be a bit more relaxed there. But I'm looking at also buying a flight from BEG to FRA a couple days later and I don't wanna do it if I'm gonna get stiffed with some bag charge, my backpack is probably a little on the big side as well, so I'm not sure how much I'll be able to jockey stuff around. The alternative is spending like an extra $50 up front and buying a LH fare and using my star gold status to have no worries about that.