This behaviour is not affected by the force flag (the force flag deletes the host even if it has any vdisk mappings). For example, the force flag does not override the policing.
If multiple hosts are mapped to the same volume, then the command will be allowed if the host that is being removed is already 'offline'. The protection will still prevent the last host being removed regardless of whether it is online or not (This is an effort to improve the policing behaviour for clustered hosts).