Of course, it's always up to the PIC. I flew 6 years as a 121 Flag carrier with people (gasp!) in the back. Lots of times we didn't have an alternate. Places like DF/W, ATL, ORD, JFK, etc, etc... It's not that big of a deal. You look at the big picture and decide if you need extra gas. So simple a caveman can do it.