Originally Posted by JDiver

What annoyance? If you fly to Mexico, the FMM fee is bundled in your airfare, but you're still paying it. F you're crossing by land or via private conveyance, it's not prepaid and needs to be paid. That's what I've done crossing by bus or POV.

Some may think the new procedure is retaliatory, but it looks more like Mexico chose to enact a revenue recovery process (as well as some border management and counting procedure) rather than continue to allow those spending some time in Mexico to walk in without paying; I can envision a substantial amount of money being collected now that was previously not.