Previously (here and here), I wrote about HB2893, which at one time called for the addition of RFID tags into vehicle registration stickers. That provision was removed, but via 100 Monkeys Typing and Corridor Watch, something else like it is either back or still in there. From the bill's text:
Sec. 601.507. SPECIAL INSPECTION CERTIFICATES. (a)
Commencing not later than January 1, 2006, the department shall
issue or contract for the issuance of special inspection
certificates to be affixed to motor vehicles that are inspected and
found to be in proper and safe condition under Chapter 548.
(b) An inspection certificate under this section must
contain a tamper-resistant transponder, and at a minimum, be
capable of storing:
(1) the transponder's unique identification number;
and
(2) the make, model, and vehicle identification number of the vehicle to which the certificate is affixed.
(c) In addition, the transponder must be compatible with:
(1) the automated vehicle registration and
certificate of title system established by the Texas Department of
Transportation; and
(2) interoperability standards established by the
Texas Department of Transportation and other entities for use of
the system of toll roads and toll facilities in this state.