let's just take one basic concept - should authorities have to get a court order to monitor each and every different communications medium a person under surveillance might use? a land line, various cell phones, email and the internet, text messaging, etc. Or should they be able to get just one warrant to cover them all?
They will do it anyway, warrant or none. Maybe not the FBI but other agencies.
Other laws already answer your questions. Just because SOME local, state and federal law enforcement officials are too lazy, stupid and/or egotistical to comply with proper legal procedures and/or applicable laws, does not mean we should continue to allow them or control-freak politicians to rape our Constitution by such legislation as the "Patriot Act".