It is a violation but not one that will never be found unless they open a permit for something else. The NEC process pretty much stops when the customer moves in and closes the door. The best hope is an insurance inspector sees it before it is a fireman on a run.
I'm surprised but it might be that more states are actually requiring more training and certification for Home Inspectors. It used to anyone with a flashlight and a clip board could call themselves a home inspector.
Just walking around looking at people's homes, I seldom actually find a panel that meets 110.26 in the strictest sense. It seems that when the original electrician placed it and established working space in front of it he also created an open space that seems to good to waste for the homeowner. There always seems to be something stored there. When I set the panel in my house I built it into a small enclosure that is too shallow to actually let you store anything inside and centered behind a 32" bi fold door. So far my wife has not tried to put anything there. I think blocking a door is just not something people are likely to do,. The door allows ready access and if you really need to get into the panel, the door lifts off the pins and you can set it aside giving you 32" of clear space. (it is still around 30 with the door open).