BS on the "absolute responsibility" and the "need" to do so. If they NEEDED to do so, it would be done every time. If it were a real issue, it wouldn't be ignored as often as it is. These companies are not stupid: they know that certain countries may fine them, and others would not.
As discussed a million times, Costa Rica and Panama are different (not to mention the US, which marches to its own beat) and have publicly made changes to their ongoing policies. If airlines truly had some issue with one-way tickets flying into Mexico, Guatemala, and Honduras (and Colombia, Ecuador, Nicaragua, etc.), do you think that travelers would virtually never have probs flying into those places except for a few exceptions? The world is made up of "rules" that don't get followed and all of us have probably already broken one by morning coffee.
No offense, but if you're constantly being asked how you're gonna manage to get yourself out of Guatemala, maybe just you look a little... rough around the edges. Not that there's anything wrong with that! Or shaving, etc.

