Currently the supplied nagios check scripts use ssh to execute the checks on a remote host. However, both nagios as well as icinga have mechanisms to run checks on remote hosts that would be much better suited for that purpose. Furthermore, since the scripts require the use of ssh, there's effectively no good way to use nagios'/icinga's own mechanism to do remote host execution.
It would be best if the checks just assumed they are run on localhost. That way the nagios/icinga admin can decide how to do remote host execution.