I vote for #4. The first 3 imply that there may be "unsafe hypermiling". The point is that the techniques described here are safe (or as safe ad driving can be). Hypermiling as defined here is inherently "safe". Other unsafe things people may do (drafting, running stop signs and red lights, etc) are NOT approved hypermiling techniques (and in fact may not save gas, or may not save as much gas as methods described here). This seems to be the most solid way to approach it.