Not only that, but if I'm reading the article correctly the ruling only refers to turning on the phone in order to find out its number. They didn't actually rifle through the phone's phone-book, call history, or anything of the sort.
"So opening the diary found on the suspect whom the police have arrested, to verify his name and address and discover whether the diary contains information relevant to the crime for which he has been arrested, clearly is permissible...
IANAL, but several sources declare that the opening of locked containers incident to arrest is determined by local enforcement policy and NOT by precedent or federal law:
http://www.fbi.gov/stats-services/publications/law-enforceme...
http://www.llrmi.com/articles/legal_questions/4-aug09.shtml
http://www.jonesdayappellate.com/files/CaseStudy/4aaa6c32-8b... [PDF] (Google Quick View of PDF: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&... )
http://www.bernardbrody.com/law-v-technology-can-the-police-...
http://findarticles.com/p/articles/mi_m2194/is_n1_v65/ai_184...