I'm not a lawyer but I am a writer and I also caught the ambiguous use of the word "believed" and understood that its use was part of a deliberate tact to mislead and deceive. And knowing that this was a flight headed to Texas, to the American Southwest, for cripes sake -- well, there's not a snowball's chance in hell that there weren't at least half a dozen Spanish-English bilingual folks on board. That ALONE told me that this AirTran and TSA account was manipulated partial-truth bullsh*t. The situation it implied (implied because of the phrase "believed it was Spanish") wasn't even remotely plausible. At least she could have said she "believed" they were speaking Balinese or Samoan or Swahili or some language where it would be believable that no one else on board could translate. I mean, come on!
Lastly, why would the two dudes not get back on the plane to reach their destination if this was a simple miscomunication?
Yep. The airline and TSA officials' claim that it was "a simple miscommunication" (whatever that is) is obviously bogus.
Good point.