It is always 'interesting' that, in arrivals, folks will abandon their trolly to run into the arms of their family/friend who have ducked under the barrier to reach them, thus making two 'lumps' of congestion in the pathway. I saw this again at LHR T5 last Sunday morning. This happens with such regularity at LHR, I wonder if it happens at other airports? Or, do they have a better 'out flow' system that limits such actions?