Here's obscure Texas law #3.
Section 22.10 - Leaving a Child in a Vehicle
Under this law, it is a class C misdemeanor to intentionally or knowingly leave a child in a motor vehicle for longer than five minutes if that the child is younger than seven years of age; and not attended by an individual in the vehicle who is 14 years of age or older.
Okay, so I might not have been in trouble because (a) I did not intentionally leave my child in the car and (b) there is a decent argument that as a stupid new parent I also did not knowingly leave him in there, and (c) I didn't leave him in there for more than 5 minutes, but others may not be so lucky. In all seriousness, however, if you ever see a small child locked in a vehicle (especially in the Texas summer heat), call the authorities immediately. This law exists because children have died from the heat or cold of being locked in a car.