It's happened already Cousin Avi,
Was there myself in the morning of the 1st Oct and saw the "trial run".
Was taxying out for a 25R departure, when we saw some Spanish Red Arrows equivalent display team come wizzing down 25R in formation with a nifty break into a left hand circuit to land in tight sequence.
A KLM 737 had just landed 25L and was taxiing to the apron via the undershoot of 25R and nearly got his tail clipped by one of the landing jets!!!
Lady on ground freq quickly told him to hold position immediately right under the approach!!!
He continued on and cleared, with the lady controller giving him an earful about not holding short 25R, KLM guy comes back quickly insisting he had been cleared to cross and all the way to stand??!!
Seems to me as if the military jet guys were ducking well under the glide to land on the piano keys not the 1000' point and combined with their shallow approach, I reckon they were over the KLM on the taxiway by about 60'!!!
Saw a few of the jets go a bit high on the profile to fly over the KLM, all fairly sporty stuff!!!!
Although this incident is probably isolated, I agree that BCN ground is very messy and one to watch out for!!