Searches of cell phones on arrest; some might suggest a warrant was appropriate

R. v. Fearon, 2014 SCC 77:

Consequently, four conditions must be met in order for the search of a cell phone or similar device incidental to arrest to comply with s. 8 . First, the arrest must be lawful. Second, the search must be truly incidental to the arrest. This requirement should be strictly applied to permit searches that must be done promptly upon arrest in order to effectively serve the law enforcement purposes.  In this context, those purposes are protecting the police, the accused or the public; preserving evidence; and, if the investigation will be stymied or significantly hampered absent the ability to promptly conduct the search, discovering evidence.  Third, the nature and the extent of the search must be tailored to its purpose.  In practice, this will mean that only recently sent or drafted emails, texts, photos and the call log will, generally, be available, although other searches may, in some circumstances, be justified.  Finally, the police must take detailed notes of what they have examined on the device and how they examined it.  The notes should generally include the applications searched, the extent of the search, the time of the search, its purpose and its duration.  The record‑keeping requirement is important to the effectiveness of after‑the‑fact judicial review.  It will also help police officers to focus on whether what they are doing in relation to the phone falls squarely within the parameters of a lawful search incident to arrest.