What's the big deal? In most states, if you refuse a sobriety test, you are convicted of DUI anyway.
If you take the test, at least you can prove that you may be a lousy driver, but you're not under the influence of anything other than your own carelessness.
HEre in TX, the loss of the license is not connected to whether or not you are guilty of the crime -- it is simply an administrative rule. Refuse and lose. The crime is treated separately.
And that amounts to proving innocence.
B*** Sh**. In most states, refusing a sobriety test gets your license suspended for refusing the test. Show me one case where a defendant was convicted of DUI for simply refusing the test.