Well firstly, no cloud storage system works with 0 locally cached data. What Uber are essentially doing is deleting evidence covered by the warrant by deleting

Well firstly, no cloud storage system works with 0 locally cached data. What Uber are essentially doing is deleting evidence covered by the warrant by deleting the local copies. The evidence may exist elsewhere, but that doesn't mean that deleting the evidence covered by the warrant is any less illegal. Once the warrant is served, anything done to delete anything off that computer is obstruction of justice, it doesn't matter what the mechanism of storage is- whether it's RAM, Hard Disk or floppy disk. Secondly, the warrant is what compels uber to give access to the evidence, there's no 'We don't feel like it right now, go to the courts to try something else'. The ability of the authorities to gain evidence through other legal avenues provides literally no defence for uber in failing to comply with a warrant.