I'd have to disagree with that Chad;
A few weeks ago a US aircraft made a forced landing in Australia and
ended up overshooting the runway, coming to rest in some poor schmucks
backyard. The entire cul de sac became off limits to those people who
lived there because of some_thing_ on the aircraft that was top secret.
It was well splashed across Aussie and New Zealand news.
Dunno about Australian law, but if that happened to me here in the
U.S., I'd sue the government for violating my 4th Amendment right to
be secure against unreasonable search and seizeure. I don't have a
problem with them coming onto my property to reclaim their aircraft
(though I'd fully expect to be compensated for damages), but the
government doesn't have any constitutionally-granted power to evict
me from my property (effectively a seizure) just because they've been
careless and allowed top secret material to fall there.
Of course, I'd probably lose the case. It's been said that "national
security" is the root key of the U.S. Constitution. The courts have
routinely allowed national security to trump rights guaranteed to the
people by the constitution, despite there being no constitutional
basis for it.
On the other hand, if they were nice about it, and asked me if I would
please agree to move into a nice hotel for a few days at their expense,
and offered reasonable compensation for my trouble, I'd be fairly likely
to agree to it.