currently in Tulum and just had this experience about 4 hours ago, ~8:30pm, June 22nd, 2017 at the Pemex on Highway 15 (Av. Coba), south of Highway 307 (Av. Tulum) heading toward the beach.
a few threads within the Tulum forum has mentioned this scam, among other scams, and within those threads MANY (too many) posts of people sharing the exact or similar experience (mostly in Tulum, at the same station or elsewhere in Mexico).
went to get gas at the Pemex station mentioned above after coming from the beach. we had half a tank and asked for a fill-up. two attendants tended to us, which was unusual from our experiences at Pemex's in Cancun and Merida where we spent most of our trip. i didnt watch the pump meter go down to 0.00 like i had done all previous times; and somehow our total ended up being ~$510 MXN. previously, when filling half a tank we usually pay roughly ~$300 pesos give or take, so this should have been another sign post that something was off.
my partner is in the driver's seat and im in the passenger seat. i pulled out a $500 MXN note, when one of the attendants started crouching down by our front left tire and asked if our car was a rental car. we said yes, and he proceeded to speak in Spanish, which neither of us were fluent in. he pretended to struggle asking if we needed air - as if he didnt know how to say the word 'air'. we declined. the second attendant was now by my window and i handed him $520 MXN. i looked away, and next thing i know he repeats the dollar amount and shows that i only handed him a $50 MXN note and a $20 MXN note. believing him, i began searching for the $500 MXN note in my wallet and car, but was incredibly distracted and stressed out by mosquitos which were eating myself and my partner alive.
we gave in, and asked if they would accept USD as we did not have enough pesos. ironically, the conversion and change they gave us was all correct and up to par. save for the fact that we had been duped and robbed of $500 pesos/$35 USD.
in the grand scheme of things it isnt much money, and at the same time it sure ruins our feelings of Tulum and the people living/working here. and to know it is happening to so many other visitors doesnt help the feeling. tourists can certainly be ignorant jerks and behave in rude, selfish ways towards locals. at the same time, not all tourists are wealthy and rich, and not all of them are jerks either. some of us have to save our earnings for these trips, and come here because its cheaper to visit than other parts of the world. having scams like this occur certainly doesnt encourage visitors to continue contributing to the local economy, and at the very least creates tensions that can lead to prejudice and discrimination.
certainly we do not look at all locals in this light, as this is our first experience with a scam in this regard, and understanding intersectionality when it comes to class and race can help put this experience into context. we need to own up on our responsibility with being diligent as travellers -
that scams are inevitable in a capitalist world (is Pemex not paying their employees enough or something??) at the same time, i wish locals participating in scams can understand the longer term, collective consequences for their short term, individual gains - and that there were meaningful ways to report these behaviours that can result in tangible changes (hey corporations, pay your employees a living wage so they dont participate in fraud, piss off tourists, and tarnish reputations of towns/cities and your own company!)
when we got back to our hotel, i couldnt get my mind off the fact that i swore i had been holding $500 MXN in my hand... so i took inventory of our cash and came to a conclusion that we had been scammed. sure enough when we looked it up there were people describing EXACTLY what we experienced at the exact same Pemex station, as well as other scams regarding credit cards. we also learned this occurs at the last Pemex gas station just before the Cancun airport and that this 500 vs. 50 switcheroo scam has been going on for at least 20 years. gas attendants are definitely learning from each other.
while this information is already out there, we wanted to highlight it again and bump this topic up as there havent been any recent threads on it from what we can see.
in short: avoid the Pemex station closest to the beach!! and in general: avoid paying for gas with large notes (stick to 50s and 100s), count it out loud in front of them, make sure the pump meter goes to 0.00 and watch them from start to finish. other folks have offered the advice of getting out of the car to watch, documenting with photos and video, dont use your credit card (they will charge it and say it was declined/that the machine is broken and so you have to pay in cash instead when you are actually now paying twice), as well as only filling up based on exact notes (i.e. filling up only $200 MXN at a time instead of filling up).
and sadly, tip gas attendants (~$10 - $20 MXN) that DONT rip you off lol....