The probable cause standard of a SCA court order is different then that of a search warrant.

I would argue that the meta-data should fall under the 4th amendment protection against unreasonable search and seizure, by your participation this data comes into existence. You may not have written it yourself, but without that person participation, the data simply does not exist.

If you rent a house, does that mean the police could search it without a search warrant? Seeing the house itself does not belong to you, you just live in it, idem rental car

By your line of thought, its reasonble for law enforccement to search any and all objects which you have not sole ownership over. Think creditcards, library cards, banking accounts, utility bills, facebook activity, rental cars, rental homes.

Without a search warrant?
Basically any piece of information that gets generated as part of a service to you instead of a product from which you transfer ownership.

So you suggest we should allow law enforcement to track cellphones without a warrant because its obvious the guy was a criminal? What if its not so obvious? Isn't that the whole point of a warrant, so you need get a court approval to see if you have reasonable evidence to do it? Could we stop fooling ourselves? Have the snowden leaks not provided us with enough enough president to confidently state the government will grossly overstep its boundaries in the name of its own perceived interest. Not the civilians, its own. To gain and keep power, one must exercises it regularly, whether justified or not. They will find a way to keep this power and therefore there will be abuse.