Many of my good friends know this method, but I am often confronted by people telling stories of being stopped and attempting to speak Spanish to the federalli's or police and ending up having problems. Let me recount the advice given to me in the early 80's when I used to drive down in a truck "sourcing" furnishings and accessories for my restaurant design business. A business associate who had already been working in Mexico for 20 years said 'NEVER SPEAK SPANISH TO THE POLICE OR FEDERALLI'S". " Only say buenos dias no matter what they say" he continued, "And by the third buenos dias they will tell you to andela"! Well he was so right and I have probably driven at least 100 times all over Mexico alone and any time I'm stopped I do that and I have never gotten past the third buenos dias without them telling me to go on. I have NEVER in 38 years paid a bribe..............and I really don't think I have ever been asked for one so I get really, really tired of people talking about the "bribe" system in Mexico.
Driving to Texas a few years ago with a good friend who grew up in Mexico and moved here in the 50's, he wanted to see the "buenos dias thing" in action. He kept quiet and was amazed how well it worked when we were stopped at a checkpoint. He could hardly contain his laughter until we drove away.