As far as I know, it's not been established factually that she or Ethan USED their passports to enter Mexico. A US driver's license is enough ID at most places.It has been said they had their passports, but we do not know this as fact.
As a local to this horrific crime and its unending repercussions, I definitely think she has a valid passport waiting for her in the DFW area.
Today, in her bond hearing, a Tarrant Co. Sheriff Deputy talked about the " meeting" Tonya and Ethan had with " many friends" on Dec. 4th. This is the " beer pong" video origin, I think.
In any case, the investigator specifically said that his source who was there when Ethan and Tonya were PLANNING over a period of hours with " friends" to disappear, the source ( a young adult like Ethan) did not retain possession of HIS passport.
The deputy didn't come right out and say " Ethan took the other guy's passport" but that was all he could have meant without coming out and saying it.
I think both of them have the means to get out of the USA and once Ethan is back in Texas, they will head to a developed country with no extradition treaty with the USA except for murder convictions. I also do not believe for one second that Fred Couch, the WV self- made millionaire father who officially is said to have made his fortune from sheet metal in a very small Texas town, is not with this plan, backing Tonya behind the scene, and will do the same or more for Ethan.
This divorce talk is something they've done twice before since Ethan killed 4 people and injured 12 more. Once, they were divorced for a short time, the other time, supposedly separated with a reconciliation.
One thing I haven't seen anyone mention is the Psych. evaluation ordered for Tonya now that she's back " home".
http://www.cnn.com/2016/01/11/us/texas-affluenza-tonya-couch/
The second article addresses the order last week for her psych. eval. I've been saying she needs this, and then appropriate treatment, since we found out about this dysfunctional family 3 years ago.
I hope Ethan also has a thorough adult-based Psych. eval. when he slinks back into town.