Here's a really simple answer: nope, he wasn't entitled to relief. Immovable obstructions do not count in hazards unless it is a local rule.
He can't take relief from anything in a hazard unless it is in a local rule. Like: if he hit the golf ball onto a platform floated in a water hazard that a car was standing on. If relief was given in a local rule, he can drop n.p.o.r. otherwise he has to play it as it lies. Now, if n.p.o.r. was in the water, then he has to drop it in the water!
One thing worries me: how the hell can they run a cart parth through an area marked with read stakes and not include that area as part of the hazard!? That is seriously bad of the Committee! Normally the Committee include bridges, paths, floats, etc. as being part of the hazard.
Sorry that you were robbed! That is a pity.
