Funny, that.
One would think that a search request of private property would be happily granted by owners of property when search is for a missing person, or any evidence of a missing persons' possible location. But here in the US it seems many more people are concerned with their right to refusal.
It's a bit 'big brother'-esk for my taste, but sometimes I sure do wish we had a federal statute akin to California's search and seizure vehicle code
http://www.dmv.ca.gov/pubs/vctop/vc/vc.htm for private land and structures. If you're paying taxes on a vehicle, and you refuse a breathalizer, your vehicle is Cali's.
Sure would save a lot of time and trouble for SAR.
(Excuse my bitter, folks! Just got turned down for a search of private property where a MP is most likely located. We obey the law, but we don't always do it happily.)