I support a facilty that uses a rather large parts washer that needs to be fed water through a garden hose. The hose is ran along the floor against the wall, but it does run about 3' below an electrical panel in the building.
Short answer? Yes, there is a 'working space' issue where the hose runs below the panel. Yet, I seriously doubt that a hose that was there ONLY while the pressure washer was in use would be considered a violation.
Likewise, the type of enclosure becomes an issue only if it is subjected to spray from the washing operations.
If they would run it in a pipe, strapped to the wall well below the panel, I think I could ignore the working space violation since it really does not impede access. The hose is troubling to me if it is just loose, kicked up against the wall. It can just as easily be kicked out into the middle of your working space and be a slip/trip hazard. Damage and leaking is also a problem.