They didn't have an arrest warrant, just a search warrant.
They formed up in the Walmart parking lot, the week before, do do this, but left when they found out that he wasn't home.
They could have kicked in his door and done the search warrant, then, without the need for 10 carloads of mall ninjas.
They needed him, to be home, for a photo op and if there was a shoot out, with him killed, all the better.
They were sending a message.
Not quite, they needed him to be home for the hit to be successful.