removing some ports on a clariion on a HP-UX host running service guard, I received the following:
$ powermt check force
Warning: CLARiiON device path c13t2d3 is currently dead.
Cannot remove device that is in use: c13t2d3
Powerpath is pretty darn smart; the last port 0 linked to a disk device was part of the same lvm volume group as one of my cluster lock disks. It wasn't even listed in as the lock disk for my cluster (in the cluster ascii file), but it was in the same volume group that the lock disk was in.
I had to stop the cluster services on the node, then powerpath allowed me to remove the connection. This node of the cluster is currently the failover node, so I was able to bring er down without any impact.