Chime me in with another vote for:

No problem if you're not walking on the moving walkways/escalators...IF you're observing the proper "stand right/walk left" protocol. Further, slightly annoying, but still no "real" problem, if I have to say "Excuse me, passing thru" to those violating said protocol, but who still promptly move aside (and often apologize).

However, PROBLEM, and will earn you a hearty and stern, "Anyone ever teach you Stand Right/Walk Left?" from me, if you dare to display a lack of disability and ANY sort of "attitude" when I politely excuse myself while trying to pass you by. And yes, it does happen more often than you would think.

Additional add-on to this discussion: PROBLEM with groups of people/family walking 3 or more abreast through an airport or other concourse, preventing faster walkers from passing by without having to somehow break through them. More than a few members of these groups have felt the wrath of a shoulder check from me (a collision I pretty much always win at 6'3" and just over 300 lbs) as I've rushed through them to make a tight flight connection in MEM's relatively narrow corridors. Clueless.