As boomy points out - there is nothing 'odd' about this at all. Australian airlines like to have terms and conditions which restrict (re)accommodation in the event of IRROPS to 'own services only'. In the US that's pretty much unheard of - they'll put you on another carrier if necessary. EU261 in Europe also helps - airlines would rather put you on another carrier than have hefty compensation to pay out. Award ticket makes no difference (nor should it) - except maybe if you go back to looking at Australia. Which should not be considered an example of best practice.