Yeah does sound like they could be quite flexible at times, the border agents ! i guess if you're with a bunch of people who have passports and you happen to forget they might just let you through if you look like a decent human being...
ah sounds like people's experiences really vary - some people got through without any certifications and no records at all while others need passport. Sounds like you can really get different treatments depending on the border agent!
yeah just curious as to how strict they are at the Mexico/US border in terms of tracking who's crossing. Some people said above in this thread that they crossed without even showing their passports/ids/birth certs...