It was my understanding that Koresh and several others made a weekly trip to Wal-Mart or Sams Club for food, like clock work once a week. And the Sheriff tried to tell the ATF they could pick him up then.
In addition, the ATF had an undercover working inside the Davidian compound who told the guy in charge of the raid that it was all blown, that the Davidians knew about the raid. And still they came.