Did a quick run to Tijuana today for FMMs, lunch, an ATM and tequila. After we got our FMMs, I asked the official about the importance of returning them when we left the country. He assured us that ...
We made it very clear that we were traveling in a vehicle, and to Palenque, Chiapas. We haven't turned in a visa in probably 20 years. Occasionally our passports are stamped as enter, sometimes not. No one has ever seemed to care. We are into easy. When we leave the country, we may very well return while our FMMs are still good, and don't want to spend another $50. Everyone works within their own comfort zone.