Frank is actually trying to kill his younger brother Joe
- Look at the episode "The Creatures Who Came On Sunday". The ep's opening titles say we're in New Mexico...but not 2 minutes later, the Hardys are pulling into a burned-out gas station, and Frank pulls out a map to trace a route to the next town — and he's looking at a map of Montana, and tracing the Missouri River to get to Great Falls. Obviously, Frank plans to dump his gullible geographically-challenged brother in the river in the back country. Muahahahaha.
- Also check out "Voodoo Doll", where Frank shoves Joe out front into danger, as the brothers are about to open a creepy mausoleum as the villain watches.
Joe: (gesturing Frank ahead) Well...you're the oldest.
Frank: Yeah, but you're more agile on your feet, and stronger.
Joe: Since when?
Frank: Since right now.
- Sole Survivor, where Frank and his father Fenton think Joe has been killed in a car crash. Frank doesn't look all that broken up about the possibility...
Fenton is trying to get rid of his sons.
- "Mystery of King Tut's Tomb" states that the Hardy Boys are driving down to meet their father in Kenya — from Cairo, in Egypt. That's a trip of over two thousand miles, at least an 8-day road trip, in a little beat-up VW microbus, through rather inhospitable terrain of desert, dry plains, and jungle, through countries that, at the time, had little-to-no tourist facilities and which were hostile towards the US. Evidently Fenton was hoping either a breakdown, terrorists, or just plain getting lost would do the young idiots in, because neither Frank nor Joe seem to care about the upcoming drive.